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Ttektronix 



2445 

OSCILLOSCOPE 

OPERATORS 

INSTRUCTION MANUAL 



Tektronix 



® 

COMMITTED TO EXCELLENCE 



PLEASE CHECK FOR CHANGE INFORMATION 
AT THE REAR OF THIS MANUAL. 



2445 

OSCILLOSCOPE 

OPERATORS 

INSTRUCTION MANUAL 



Tektronix, Inc. 

P.O. Box 500 

Beaverton, Oregon 97077 Serial Number 



070-3830-00 First Printing OCT 1982 

Product Group 38 Revised NOV 1984 



Copyright © 1982 Tektronix, Inc. All rights reserved. 
Contents of this publication may not be reproduced in any 
form without the written permission of Tektronix, Inc. 

Products of Tektronix, Inc. and its subsidiaries are covered 
by U.S. and foreign patents and/or pending patents. 

TEKTRONIX, TEK, SCOPE-MOBILE, and fflf are 
registered trademarks of Tektronix, Inc. TELEQUIPMENT 
is a registered trademark of Tektronix U.K. Limited. 

Printed in U.S.A. Specification and price change privileges 
are reserved. 



INSTRUMENT SERIAL NUMBERS 

Each instrument has a serial number on a panel insert, tag, 
or stamped on the chassis. The first number or letter 
designates the country of manufacture. The last five digits 
of the serial number are assigned sequentially and are 
unique to each instrument. Those manufactured in the 
United States have six unique digits. The country of 
manufacture is identified as follows: 

B000000 Tektronix, Inc., Beaverton, Oregon, USA 

100000 Tektronix Guernsey, Ltd., Channel Islands 

200000 Tektronix United Kingdom, Ltd., London 

300000 Sony/Tektronix, Japan 

700000 Tektronix Holland, NV, Heerenveen, 
The Netherlands 



2445 Operators 



TABLE OF CONTENTS 



Page 

LIST OF ILLUSTRATIONS ii 

LIST OF TABLES ii 

OPERATORS SAFETY SUMMARY iii 

SECTION 1 SPECIFICATION 

INTRODUCTION 1-1 

PERFORMANCE CONDITIONS .. . 1-1 



SECTION 2 PREPARATION FOR USE 

SAFETY 2-1 

LINE VOLTAGE SELECTION 2-1 

LINE FUSE 2-1 

POWER CORD 2-1 

INSTRUMENT COOLING 2-1 

START-UP 2-2 

REPACKAGING FOR SHIPMENT. . 2-2 



SECTION 3 CONTROLS, CONNECTORS, 
AND INDICATORS 

POWER AND DISPLAY 3-1 

VERTICAL 3-2 

HORIZONTAL AND DELTA 

MEASUREMENT 3-4 

TRIGGER 3-7 

REAR PANEL 3-9 

READOUT DISPLAY 3-11 



SECTION 4 OPERATING CONSIDERATIONS 

GRATICULE 4-1 

TIME AND VOLTAGE 

MEASUREMENTS 4-1 

GROUNDING 4-1 

SIGNAL CONNECTIONS 4-2 

INPUT-COUPLING CAPACITOR 

PRECHARGING 4-2 

EXTERNALTRIGGERING 4-2 



Page 

SECTION 5 OPERATOR'S CHECKS AND 
ADJUSTMENTS 

INTRODUCTION 5-1 

INITIAL SETUP 5-1 

TRACE ROTATION 

ADJUSTMENT 5-1 

ASTIGMATISM ADJUSTMENT ... 5-2 
AUTO DC BALANCE 

ADJUSTMENT 5-2 

PROBE LOW-FREQUENCY 

COMPENSATION 5-2 

MATCHING CHANNEL 2 DELAY. . 5-3 

AMPLITUDE CHECK 5-4 

TIMING CHECK 5-4 

SECTION 6 BASIC APPLICATIONS 

INDEX OF PROCEDURES 6-1 

VOLTAGE MEASUREMENT 6-1 

VOLTAGE RATIO 6-2 

ALGEBRAIC ADDITION AND 
ELIMINATING COMMON-MODE 

SIGNALS 6-3 

TIME INTERVAL 6-4 

FREQUENCY 6-4 

TIME DIFFERENCE BETWEEN 

TWO TIME-RELATED PULSES ... 6-5 

TIME RATIO 6-5 

PHASE DIFFERENCE BETWEEN 

TWO TIME-RELATED SIGNALS . . 6-6 

SMALL-ANGLE PHASE 

DIFFERENCE 6-6 

DELAYED-SWEEP OPERATION. . . 6-7 

SECTION 7 OPTIONS AND ACCESSORIES 

INTRODUCTION 7-1 

OPTION 1R 7-1 

POWER CORD OPTIONS 7-1 

STANDARD ACCESSORIES 7-2 

OPTIONAL ACCESSORIES 7-2 

APPENDIX A POWER-UP TESTS 

KERNEL TESTS A-1 

CONFIDENCE TESTS A-1 

CHANGE INFORMATION 



2445 Operators 



LIST OF ILLUSTRATIONS 



Figure Page 

The 2445 Oscilloscope iv 

2-1 Line selector switch, line fuse, and detachable power cord 2-2 

3-1 Power and display controls 3-1 

3-2 Vertical controls and CH 1 OR X and CH 2 connectors 3-2 

3-3 Channel 3 and Channel 4 controls and connectors and CALIBRATOR output 3-3 

3-4 Horizontal and delta measurement controls 3-4 

3-5 Trigger controls and indicators 3-7 

3-6 Rear-panel controls and connectors 3-10 

3-7 Readout display locations 3-11 

4-1 Graticule measurement markings 4-1 

5-1 Probe low-frequency compensation 5-3 

6-1 Instantaneous dc levels 6-1 

6-2 Voltage ratios 6-2 

6-3 Eliminating common-mode signals 6-3 

6-4 Measuring rise times 6-4 

6-5 Time difference between two time-related pulses (cursor method) 6-5 

6-6 Time ratios (duty cycles) 6-6 

6-7 Phase difference between two time-related signals 6-7 

6-8 Small-angle phase difference 6-7 

6-9 Time difference between two time-related pulses (delayed-sweep method) 6-9 



LIST OF TABLES 



Table Page 

1-1 Electrical Characteristics 1-2 

1-2 Environmental Characteristics 1-9 

1-3 Mechanical Characteristics 1-10 

2-1 Voltage, Fuse, and Power-Cord Data 2-3 

A-1 Confidence Test Numbers and Descriptions A-1 



2445 Operators 



OPERATORS SAFETY SUMMARY 



The general safety information in this part of the summary is for both operating and servicing personnel. Specific warnings 
and cautions will be found throughout the manual where they apply and do not appear in this summary. 



Terms in This Manual 

CAUTION statements identify conditions or practices 
that could result in damage to the equipment or other 
property. 

WARNING statements identify conditions or practices 
that could result in personal injury or loss of life. 



Grounding the Product 

This product is grounded through the grounding conductor 
of the power cord. To avoid electrical shock, plug the 
power cord into a properly wired receptable before con- 
necting to the product input or output terminals. A 
protective ground connection by way of the grounding 
conductor in the power cord is essential for safe operation. 



Terms as Marked on Equipment 

CAUTION indicates a personal injury hazard not imme- 
diately accessible as one reads the markings, or a hazard to 
property, including the equipment itself. 

DANGER indicates a personal injury hazard immediately 
accessible as one reads the marking. 



Symbols in This Manual 

symbol 



A 



This symbol indicates where applicable 
cautionary or other information is to be 
found. For maximum input voltage see 
Table 1-1. 



Symbols as Marked on Equipment 

£ DANGER - High voltage. 

hi) Protective ground (earth) terminal. 
/v\ ATTENTION - Refer to manual. 



Power Source 

This product is intended to operate from a power source 
that does not apply more than 250 volts rms between the 
supply conductors or between either supply conductor and 
ground. A protective ground connection by way of the 
grounding conductor in the power cord is essential for safe 
operation. 



Danger Arising From Loss of Ground 

Upon loss of the protective-ground connection, all acces- 
sible conductive parts (including knobs and controls that 
may appear to be insulating) can render an electric shock. 



Use the Proper Power Cord 

Use only the power cord and connector specified for 
your product. 

Use only a power cord that is in good condition. 

For detailed information on power cords and connectors 
see Table 2-1. 



Use the Proper Fuse 

To avoid fire hazard, use only a fuse of the correct type, 
voltage rating and current rating as specified in the parts 
list for your product. 

Do Not Operate in Explosive Atmospheres 

To avoid explosion, do not operate this product in an 
explosive atmosphere unless it has been specifically cer- 
tified for such operation. 

Do Not Remove Covers or Panels 

To avoid personal injury, do not remove the product 
covers or panels. Do not operate the product without the 
covers and panels properly installed. 



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2445 Operators 



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The 2445 Oscilloscope. 



3830-01 



IV 



Section 1 -2445 Operators 



SPECIFICATION 



INTRODUCTION 

The TEKTRONIX 2445 Oscilloscope is a portable 
150-MHz instrument having a four-channel vertical deflec- 
tion system. Channel 1 and Channel 2 provide calibrated 
deflection factors from 2 mV per division to 5 V per 
division. For each of these channels, input impedance is 
selectable between two values: either 1 Mfi in parallel 
with 15 pF, or 5012 internal termination. Input-signal 
coupling with 1-MJ2 impedance can be selected as either 
AC or DC. Channel 3 and Channel 4 have deflection factors 
of either 0.1 V or 0.5 V per division. Each of these channels 
has an input impedance of 1 M£2 in parallel with 15 pF, 
with DC input-signal coupling. Trigger circuits enable stable 
triggering over the full bandwidth of the vertical system. 



The horizontal deflection system provides calibrated 
sweep speeds from 1.5 s per division to 1 ns per division. 
Drive for the horizontal deflection system is obtained from 
a choice of A, B delayed, A alternated with B delayed 
sweeps, or CH 1 (for the X-Y display mode). 



For part numbers and further information about both 
standard and optional accessories, refer to "Options and 
Accessories" (Section 7) of this manual. Your Tektronix 
representative or local Tektronix Field Office can also 
provide accessories information and ordering assistance. 



PERFORMANCE CONDITIONS 



The following electrical characteristics (Table 1-1) 
are valid for the 2445 when it has been adjusted at an 
ambient temperature between +20 C and +30° C, has had 
a warm-up period of at least 20 minutes, and is operating 
at an ambient temperature between — 15°C and +55°C 
(unless otherwise noted). 



The 2445 incorporates alphanumeric crt readouts of the 
vertical and horizontal scale factors, the trigger levels, 
time-difference measurement values, voltage-difference 
measurement values, and certain auxiliary information. 



Items listed in the "Performance Requirements" column 
are verifiable qualitative or quantitative limits that define 
the measurement capabilities of the instrument. 



The 2445 Oscilloscope is shipped with the following 
standard accessories: 

2 Probe packages 

1 Snap-lock accessories pouch 

1 Zip-lock accessories pouch 

1 Operators manual 

1 Service manual 

1 Power cord (installed) 

1 2-A, 250-V f use 

1 Clear plastic crt filter 

1 Blue plastic crt filter (installed) 

1 Front-panel cover 

1 Operators pocket reference card 



Environmental characteristics are given in Table 1-2. 
The 2445 Oscilloscope meets the environmental require- 
ments of MIL-T-28800C for Type III, Class 3, Style C 
equipment, with the humidity and temperature require- 
ments defined in paragraphs 3.9.2.2, 3.9.2.3, and 3.9.2.4. 



Mechanical 
Table 1-3. 



characteristics of the 2445 are listed in 



1-1 



Specification— 2445 Operators 



Table 1-1 
Electrical Characteristics 



Characteristics 



Performance Requirements 



VERTICAL DEFLECTION SYSTEM-CHANNEL 1 AND CHANNEL 2 



Deflection Factor 
Range 



Accu racy 

+15°Cto+35°C 



-15°C to +15°C and +35°C to +55°C 

AV Accuracy (using cursors over entire 
graticule area) 

+ 15°Cto +35°C 



-15°C to +15° C and +35°C to +55°C 



AV Range 



Variable Range 



Frequency Response (3 dB bandwidth) 



-15°Cto + 55°C 



-15°C to + 35°C 
+ 35°Cto +55°C 



AC Coupled Lower -3 dB Point 
1X Probe 



1 0X Probe 



Step Response 
Rise Time 



Common-mode Rejection Ratio (CMRR) 



2 mV per division to 5 V per division in a 1-2-5 sequence of 1 1 steps. 



Within ±2% at any VOLTS/DIV setting for a 4- or 5-division signal 
centered on the screen. 



Add 1% to +15°C-to-+35°C specification. 



: (1 .25% of reading + 0.03 division + signal aberrations). 



Add 1% of reading to -t-15°C-to-+35 C specification. 



± 8 times the VOLTS/DIV switch setting. 



Continuously variable between VOLTS/DIV switch settings. Extends 
deflection factor of the 5 V per division setting to at least 12.5 V 
per division. 



Six-division reference signal from a terminated 50-fi system, with 
VAR VOLTS/DIV control in calibrated detent. 



VOLTS/DIV 
setting 



2mV 



5 mV or greater 



5 mV or greater 



— 3 dB bandwidth 

with standard-accessory 

probe or internal 

50-fl termination 



DC to 80 MHz 



DC to 150 MHz 



DC to 100 MHz 



—4.7 dB bandwidth 

with 50-Q external 

termination on 

1-MQ input 



DC to 80 MHz 



DC to 150 MHz 



DC to 100 MHz 



10 Hz or less. 



1 Hz or less. 



2.33 ns or less for VOLTS/DIV switch settings of 5 mV and up 
(calculated). 

4.4 ns or less for VOLTS/DIV switch setting of 2 mV (calculated). 

Rise time calculated from: bandwidth x rise time = 0.35. 



At least 20:1 at 50 MHz for common-mode signals of eight divisions 
or less, with VAR VOLTS/DIV control adjusted for best CMRR at 
50 kHz at any VOLTS/DIV switch setting from 5 mV to 5 V; at 
least 20:1 at 20 MHz at 2 mV per division. 



1-2 



REV MAR 1984 



Specification— 2445 Operators 



Table 1-1 (cont) 



Characteristics 



Performance Requirements 



VERTICAL DEFLECTION SYSTEM-CHANNEL 1 AND CHANNEL 2 (cont) 



Channel Isolation 



Displayed Channel 2 Signal Delay with Respect 
to Channel 1 Signal 



Input Rand C(1 M£2) 
Resistance 



Capacitance 



Maximum Input Voltage /K 



Input R (50 £1) 
Resistance 



VSWR (DC to 150 MHz) 



Maximum Input Voltage /[\ 
(DC Coupling Only) 



Cascaded Operation 



Bandwidth 



Deflection Factor 



100:1 or greater attenuation of the deselected channel at 100 MHz; 
50:1 or greater attenuation at 150 MHz, for an eight-division input 
signal from 2 mV per division to 500 mV per division, with equal 
VOLTS/DIV switch settings on both channels. 



Adjustable through a range of at least -500 ps to +500 ps. 



1 M£2 ±0.5%. 



15pF±2pF. 



400 V (dc + peakac). 

800 V p-p ac at 10 kHz or less. 



50J2±1%. 



1.3:1 or less. 



5 V rms; 0.5 W-seconds during any 1-s interval for instantaneous 
voltage from 5 V to 50 V. 



CH 2 SIGNAL OUT into Channel 1 input; DC coupled using a 
50-O RG-58C/U coaxial cable, terminated in 50 £1 at the Channel 1 
input. Channel 1 and Channel 2 VOLTS/DIV switch set to 2 mV. 

Dc to 50 MHz or greater. 



400 ;uV per division ±10%. 



VERTICAL DEFLECTION SYSTEM-CHANNEL 3 AND CHANNEL 4 



Deflection Factor 
Values 


0.1 V per division and 0.5 V per division. 


Accuracy 


Within ±10%. 


Frequency Response (3-d B Bandwidth) 


Six-division reference signal, from a terminated 50-f2 system. 




-3 dB Bandwidth 
With standard accessory probe 


-4.7 dB Bandwidth 
With external 50-fi termination 




DC to 150 MHz 


DC to 150 MHz 


Step Response 
Rise Time 


2.33 ns or less (calculated from bandwidth). 


Channel Isolation 


50:1 or greater attenuation of the deselected channel at 100 MHz 
with an eight-division input signal. 



REV MAY 1984 



1-3 



Specification— 2445 Operators 



Table 1-1 (cont) 



Characteristics 



Performance Requirements 



VERTICAL DEFLECTION SYSTEM-CHANNEL 3 AND CHANNEL 4 (cont) 



Input R and C 
Resistance 


1 MS2±1%. 


Capacitance 


15pF±3pF. 


Maximum Input Voltage /K 


400 V (dc + peak ac); 

800 V p-p ac at 10 kHz or less. 



VERTICAL DEFLECTION SYSTEM-ALL CHANNELS 



Low-frequency Linearity 


0.1 division or less compression or expansion of a two-division, 
center-screen signal when positioned anywhere within the graticule 
area. 


Bandwidth Limiter 


Reduces upper 3-dB bandpass to a limit of 13 MHz to 24 MHz. 


Vertical Signal Delay 


At least 20 ns of the sweep is displayed before the triggering event 
is displayed. 


Chopped Mode Switching Rate 


Vertical display switches sequentially through the selected channels 
at the chop switching rate. If the B SEC/DIV switch is set to sweep 
speeds outside the range of 20 /is per division to 2 f/s per division, 
the switching rate is 1 MHz ±0.2% (dual-channel cycle rate of 
500 kHz). If the B SEC/DIV switch is set within the range of 20 jus 
per division to 2 pis per division, the switching rate is 2.5 MHz ±0.2% 
(dual-channel cycle rate of 1.25 MHz). At all sweep speeds, the 
chop switching rate is desynchronized with the sweep frequency to 
minimize waveform breaks when viewing repetitive signals. 



TRIGGERING 



Minimum P-P Signal Amplitude for Stable Triggering 
from Channel 1 or Channel 2 Source 
DC Coupled 


0.35 division from dc to 50 MHz, increasing to 1 division at 150 MHz, 
1 .5 divisions at 250 MHz in ADD MODE. 


NOISE REJ Coupled 


1.2 divisions or less from dc to 50 MHz, increasing to 3 divisions at 
150 MHz, 4.5 divisions at 250 MHz in ADD MODE. 


AC Coupled 


0.35 division from 60 Hz to 50 MHz, increasing to 1 division at 
150 MHz, 1.5 divisions at 250 Mhz in ADD MODE. Attenuates 
signals below 60 Hz. 


HF REJ Coupled 


0.5 division from dc to 30 kHz. 


LF REJ Coupled 


0.5 division from 80 kHz to 50 MHz, increasing to 1 division at 
150 MHz, 1.5 divisions at 250 MHz in ADD MODE. 


Minimum P-P Signal Amplitude for Stable Triggering 
from Channel 3 or Channel 4 Source 


Amplitudes are one-half of Channel 1 or Channel 2 source 
specification. 


Minimum P-P Signal Amplitude for Stable Triggering 
from Composite, Multiple Channel Source in ALT 
Vertical Mode 


Add 1 division to single-channel source specifications. 



1-4 



REV MAY 1984 



Specification— 2445 Operators 



Table 1-1 (cont) 



Characteristics 



Performance Requirements 



TRIGGERING (cont) 



Maximum P-P Signal Rejected by NOISE REJ 
COUPLING for Signals Within the Vertical Bandwidth 

Channel 1 or Channel 2 Source 


0.4 division or greater for VOLTS/DIV switch settings of 10 mV 
and higher. 


Channel 3 or Channel 4 Source 


0.2 division or greater. 


Jitter 


Less than 100 ps at 150 MHz with A and B SEC/DIV switch set to 
10 ns, X10 MAG on, and 5 divisions of amplitude. 


LEVEL Control Range 

Channel 1 or Channel 2 Source 


+ 18 times the VOLTS/DIV switch setting. 


Channel 3 or Channel 4 Source 


± 9 times the VOLTS/DIV switch setting. 


LEVEL Control Readout Accuracy (for triggering 
signals with transition times greater than 10 ns) 

Channel 1 or Channel 2 Source 

DC Coupled 

+15°Cto+35°C 


Within ± [3% of setting + 3% of p-p signal + 0.2 division + 0.5 mV 
+ (0.5 mV x probe attenuation factor)]. 


-15°Cto+55°C 
(excluding +15°C to +35° C) 


Add (1.5 mV x probe attenuation factor) to the specification listed 
for+15°Cto+35°C. 


NOISE REJ Coupled 


Add ±0.6 division to the DC Coupled specification. 


Channel 3 or Channel 4 Source 


Within ±[3% of setting + 4% of p-p signal + 0.1 division + (0.5 mV 
x probe attenuation factor)]. 


SLOPE Selection 


Conforms to trigger-source waveform or ac power-source waveform. 


AUTO LVL Mode Maximum Triggering Signal Period 
A SEC/DIV Switch Setting Less than 10 ms 


At least 20 ms. 


A SEC/DIV Switch Setting from 10 ms to 50 ms 


At least four times the A SEC/DIV switch setting. 


A SEC/DIV Switch Setting from 100 msto 500 ms 


At least 200 ms. 


AUTO Mode Maximum Triggering Signal Period 
A SEC/DIV Switch Setting Less than 10 ms 


At least 80 ms. 


A SEC/DIV Switch Setting from 10 ms to 50 ms 


At least 16 times the A SEC/DIV switch setting. 


A SEC/DIV Switch Setting from 100 msto 500 ms 


At least 800 ms. 


AUTO LVL Mode Trigger Acquisition Time 


Eight to 100 times the AUTO LVL Mode maximum triggering-signal 
period, depending on the triggering-signal period and waveform. 



REV MAY 1984 



1-5 



Specification-2445 Operators 



Table 1-1 (cont) 



Characteristics 



Performance Requirements 



HORIZONTAL DEFLECTION SYSTEM 



A Sweep Time Base Range 



1 s per division to 10 ns per division in a 1-2-5 sequence of 25 steps. 
X10 MAG feature extends maximum sweep speed to 1 ns per 
division. 



B Sweep Time Base Range 



50 ms per division to 10 ns per division in a 1-2-5 sequence of 
21 steps. X10 MAG feature extends maximum sweep speed to 
1 ns per division. 



SEC/D I WAR Control 



Continuously variable and calibrated between settings of the SEC/ 
D I V switch. Extends slowest A Sweep speed to 1.5 s per division. 
Operates in conjunction with the A SEC/D IV switch when A and B 
are locked together; operates in conjunction with the B SEC/D IV 
switch when A and B are not locked together. 



Timing Accuracy (+15°Cto +35 C, SEC/DIV 
switch set to 0.1 s per division or less) 

A and B Sweep Accuracy, Time Intervals 
Measured at Vertical Center with SEC/DIV 
VAR Control in Detent 



Unmagnified 



± (0.7% of time interval 
+ 0.6% of full scale). 



Magnified 



+ (1.2% of time interval 
+ 0.6% of full scale). 



0.6% of full scale is 0.06 division. 



At Accuracy, Time Intervals Measured with 
Cursors, Anywhere on the Graticule 
(A Sweep Only) 



Unmagnified 



± (0.5% of time interval 
+ 0.3% of full scale). 



Magnified 



± (1% of time interval 
+ 0.3% of full scale). 



At Accuracy, Time Intervals Measured with 
Delayed B Sweep with Both Delays Set at 1% 
or More of Full Scale from Minimum Delay 
(no ? displayed in readout) 



+ (0.3% of time interval + 0.1% of full scale). 



Delay Accuracy, A Sweep Trigger Point to Start 
of B Sweep 



± (0.3% of delay setting + 0.6% of full scale) - 25 ns. 



Timing Accuracy (A SEC/DIV switch set to 0.5 s or 
0.2 s per division) 



Add ±0.5% of time interval to all accuracy specifications. 



Timing Accuracy (A SEC/DIV switch set to 1 s per 
division) 



Add ±2% of time interval to all accuracy specifications. 



Timing Accuracy (SEC/DIV VAR control out of 
detent) 



Add 2% of time interval to the A and B Sweep Accuracy 
specification. 



Timing Accuracy (—15 Cto+15 C and +35 C 
to+55°C) 

At Readout Resolution 



Add ±0.2% of time interval to all At and delay specifications. Add 
±0.5% of time interval to A and B Sweep accuracy specifications. 



Greater of either 20 ps or 0.025% of full scale. 



At Range 



± 10 times the A SEC/DIV switch setting. 



Delay Pickoff Jitter 



Within 0.004% (one part or less in 25,000) of the maximum 
available delay, plus 100 ps. 



1-6 



Specification-2445 Operators 



Table 1-1 (cont) 



Characteristics 



Performance Requirements 



HORIZONTAL DEFLECTION SYSTEM (cont) 



Delay Time Position Range 


to 9.95 times the A SEC/DIV switch setting. Main sweep triggering 
event is observable on delayed sweep with zero delay setting. 


X-Y Operation 

X-Axis Deflection Factor 
Range 


Same as Channel 1. 


Accuracy 


Same as Channel 1 . 


Variable Range 


Same as Channel 1 . 


X-Axis Bandwidth 


Dc to 3 MHz. 


Input R and C 


Same as Channel 1. 


Phase Difference Between X and Y with Normal 
Bandwidth 


1° or less from dc to 1 MHz; 
3° or less from 1 MHz to 2 MHz. 


X-Axis Low-Frequency Linearity 


0.2 division or less compression or expansion of a two-division, 
center-screen signal when positioned within the display area. 



CURSOR AND FRONT-PANEL DISPLAY 



Cursor Position Range 
Delta Volts (AV) 


At least the center 7.6 vertical divisions. 


Delta Time (At) 


At least the center 9.6 horizontal divisions. 


Minimum Setup Time Required to Maintain 
Front-panel Settings at Power-down 


10 seconds or less. 



Z-AXIS INPUT 



Sensitivity 


Positive voltage decreases intensity. From dc to 2 MHz, +2 V blanks 
a maximum-intensity trace; from 2 MHz to 20 MHz, +2 V modulates 
a normal-intensity trace. 


Input Resistance 


10kI2±10%. 


Maximum Input Voltage /j\ 


±25 V peak; 25 V p-p ac at 10 kHz or less. 



SIGNAL OUTPUTS 



CALIBRATOR 

Output Voltage and Current 



Repetition Period 
Accuracy 



0.4 V ±1% into a 1-MJ2 load, 0.2 V ±1.5% into a 50-fi load, or 
8 mA ±1.5% into a short circuit, with the A SEC/DIV switch set to 
1 ms per division. 



Two times the A SEC/DIV switch setting within the range of 200 ns 
to 200 ms. 

+0.1%, measured with SGL SEQ A TRIGGER MODE selected. 



1-7 



Specification— 2445 Operators 



Table 1-1 (cont) 



Characteristics 



Performance Requirements 



SIGNAL OUTPUTS (cont) 



CALIBRATOR (cont) 
Symmetry 


Duration of high portion of output cycle is 50% of output period 
± (lesser of 500 ns or 25% of period). 


Jitter of Pulse Period or Pulse Width 


10 nsor less. 


CH 2 SIGNAL OUT 
Output Voltage 


20 mV per division ±10% into 1 Mfi; 
10 mV per division ±10% into 50 f2. 


Offset 


±10 mV into 50 Q,, when dc balance has been performed within 
±5 C of the operating temperature. 


A GATE OUT and B GATE OUT 
Output Voltage 


2.4 V to 5 V positive-going pulse, starting at V to 0.4 V. 


Output Drive 


Will supply 400 juA during HI state; will sink 2 mA during LO state. 



CRT 



Display 


80 mm x 100 mm. 


Standard Phosphor 


P31. 



Nominal Accelerating Potential 



16 kV. 



AC POWER SOURCE 



Source Voltage 
Ranges 



115V 


90 V to 132 V. 


230 V 


180 V to 250 V. 


Source Frequency 


48 Hz to 440 Hz. 



Fuse Rating 


2 A, 250 V, AGC/3AG, Fast blow; 

or 1.6 A, 250 V, 5 x 20 mm. Quick-acting (F). 


Power Consumption 
Typical 


70W(140VA). 


Maximum 


120W(180VA). 


Primary Circuit Dielectric Voltage Withstand Test 


1500 V rms, 60 Hz for 10 s without breakdown. 


Primary Grounding 


Type test to 0.1 Q. maximum. Routine test to check grounding 
continuity between chassis ground and protective earth ground. 



1-8 



Specification-2445 Operators 



Table 1-2 
Environmental Characteristics 



Characteristics 


Performance Requirements 


Temperature 
Operating 


The 2445 Oscilloscope meets the environmental requirements of 
MIL-T-28800C for Type III, Class 3, Style C equipment, with the 
humidity and temperature requirements defined in paragraphs 
3.9.2.2, 3.9.2.3, and 3.9.2.4. 

-15°Cto + 55°C. 


Nonoperating (storage) 


-62°Cto + 85°C. 


Altitude 
Operating 


To 15,000 ft. Maximum temperature decreases 1°C for each 1,000 
ft. above 5,000 ft. 


Nonoperating (storage) 


To 50,000 ft. 


Humidity (operating and nonoperating) 


Stored at 95% relative humitidy for five cycles (120 hours) from 30°C 
to 60°C, with operational performance checks at 30°C and 55°C. 


Vibration (operating) 


1 5 minutes along each of three axes at a total displacement of 0.025 
inch p-p (4 g at 55 Hz), with frequency varied from 1 Hz to 55 Hz in 
one-minute sweeps. Held 1 minutes at each major resonance, or if 
none existed, held 10 minutes at 55 Hz (75 minutes total test time). 


Shock (operating and nonoperating) 


50 g, half-sine, 1-ms duration, three shocks on each face, for a total 
of 1 8 shocks. 


Transit Drop (not in shipping package) 


12-inch drop on each corner and each face (MIL-T-28800C, 
para 3.9.5.2 and 4.5.5.4.2). 


Bench Handling (with and without cabinet installed) 


MIL-STD-810C, Method 516.2, Procedure V (MIL-T-28800C, 
para 4.5.5.4.3). 


EMI (electromagnetic interference) 


Meets MIL-T-28800C; MIL-STD-461B, Part 4 (CE-03 and CS-02), 
Part 5 (CS-06 and RS-02), and Part 7 (CS-01, RE-02, and RE- 
03— limited to 1 GHz); VDE 0871, Catagory B; Part 15 of FCC Rules 
and Regulations, Subpart J, Class A; and Tektronix Standard 062- 
2866-00. 


Topple (operating with cabinet installed) 


Set on rear feet and allowed to topple over onto each of four 
adjacent faces (Tektronix Standard 062-2858-00). 


Packaged Transportation Drop 


Meets the limits of the National Safe Transit Association test 
procedure 1A-B-2; 10 drops of 36 inches (Tektronix Standard 062- 
2858-00). 


Packaged Transportation Vibration 


Meets the limits of the National Safe Transit Association test 
procedure 1A-B-1; excursion of 1 inch p-p at 4.63 Hz (1.1 g) for 30 
minutes (Tektronix Standard 062-2858-00). 



REV MAY 1984 



1-9 



Specification-2445 Operators 



Characteristics 



Weight 

With Accessories and Pouch 



Without Accessories and Pouch 



Domestic Shipping Weight 

Height 

With Feet and Accessories Pouch 



Without Accessories Pouch 



Width (with handle) 



Depth 

With Front-Panel Cover 



With Handle Extended 



Cooling 



Finish 



Construction 



Table 1-3 
Mechanical Characteristics 



10.2 kg (22.4 lb). 



9.3 kg (20.5 lb). 



12.8 kg (28.2 lb). 



190 mm {7.5 in). 



160 mm (6.3 in). 



330 mm (13.0 in) 



434 mm (17.1 in). 



505 mm (19.9 in). 



Forced-air circulation. 



Description 



Tektronix Blue vinyl-clad material on aluminum cabinet. 



Aluminum-alloy chassis (sheet metal). Die-cast aluminum front 
panel. Glass-laminate circuit boards. 



1-10 



Section 2-2445 Operators 



PREPARATION FOR USE 



SAFETY 

This section tells how to prepare for and to proceed 
with the initial start-up of the TEKTRONIX 2445 
Oscilloscope. 



2. Pull the cap (with the attached fuse inside) out of 
the fuse holder. 



3. Verify proper fuse value (see Table 2-1). 



Refer to the Safety Summary at the front of this manual 
for power source, grounding, and other safety consider- 
ations pertaining to the use of the instrument. Before con- 
necting the oscilloscope to a power source, read entirely 
both this section and the Safety Summary. 




This instrument may be damaged if operated with 
the LINE VOLTAGE SELECTOR switch set for the 
wrong applied ac input-source voltage or if the 
wrong line fuse is installed. 



LINE VOLTAGE SELECTION 

The 2445 operates from either a 115-V or a 230-V 
nominal ac power-input source having line frequency 
ranging from 48 Hz to 440 Hz. Before connecting the 
power cord to a power-input source, verify that the LINE 
VOLTAGE SELECTOR switch, located on the rear panel 
(see Figure 2-1), is set for the correct nominal ac input- 
source voltage. To convert the instrument for operation 
from one line-voltage range to the other, move the LINE 
VOLTAGE SELECTOR switch to the correct nominal 
ac source-voltage setting (see Table 2-1). The detachable 
power cord may have to be changed to match the particular 
power-source output. 



4. Install the proper fuse and reinstall the fuse-holder 
cap. 



NOTE 

The two types of fuses listed are not directly inter- 
changeable; they require different types of fuse caps. 



POWER CORD 

This instrument has a detachable, three-wire power cord 
with a three-contact plug for connection to both the power 
source and protective ground. The power cord is secured to 
the rear panel by a cord-set-securing clamp. The protective- 
ground contact on the plug connects (through the power- 
cord protective grounding conductor) to the accessible 
metal parts of the instrument. For electrical-shock pro- 
tection, insert this plug into a power-source outlet that has 
a properly grounded protective-ground contact. 



Instruments are shipped with the required power cord 
as ordered by the customer. Available power-cord informa- 
tion is presented in Table 2-1, and part numbers are listed 
in "Options and Accessories" (Section 7). Contact your 
Tektronix representative or local Tektronix Field Office 
for additional power-cord information. 



LINE FUSE 



INSTRUMENT COOLING 



To verify that the instrument power-input fuse is of 
proper value for the nominal ac source voltage selected, 
perform the following procedure: 

1. Press in the fuse-holder cap and release it with a 
slight counterclockwise rotation. 



To prevent instrument damage from overheated com- 
ponents, adequate internal airflow must be maintained at 
all times. Before turning on the power, first verify that both 
the air-intake holes on the bottom of the cabinet and the 
fan-exhaust holes in the rear panel are free of any obstruc- 
tion to airflow. 



2-1 



Preparation for Use-2445 Operators 




LINE FUSE 



LINE SELECTOR 
SWITCH 



CAUTION 



5 SKn-wrwi,*. urnur. If* Ml 






! IKlBOUli «£ flfAMffTOl OttfiON U.8A. 







_ . _. _ CH 2 SIGNAl OUT 

POWER CORD RECEPTACLE utm «ro son 



3830-03 



Figure 2-1. Line selector switch, line fuse, and detachable power cord. 



START-UP 

The 2445 automatically performs power-up tests each 
time the instrument is turned on. The purpose of these 
tests is to provide the user with the highest possible con- 
fidence level that the instrument is fully functional. If no 
faults are encountered, the power-up tests normally will be 
completed in under five seconds, after which the instru- 
ment will enter the normal operating mode. A failure of 
any of the power-up tests will be indicated by either a 
flashing TRIG'D indicator on the instrument front panel or 
a bottom-line readout on the crt in the form: TEST XX 
FAIL YY (where XX is the test number and YY is the 
failure code of the failed test). 



If a failure of any power-up test occurs, the instrument 
may still be usable for some applications. To put the 
instrument into the operating mode after a power-up test 
failure, press the A/B TRIG button. If the instrument then 
functions for your particular measurement requirement, it 
may be used, but refer it to a qualified service technician 
for repair of the problem at the earliest convenience. 
Additional information on the power-up tests may be 
found in Appendix A at the rear of this manual. Consult 
your service department, your local Tektronix Service 
Center, or nearest Tektronix representative if additional 
assistance is needed. 



REPACKAGING FOR SHIPMENT 

If this instrument is to be shipped by commercial 
transportation, it is recommended that it be packaged in 
the original manner. The carton and packaging material in 
which your instrument was shipped to you should be saved 
and used for this purpose. 



If the original packaging is unfit for use or is not avail- 
able, repackage the instrument as follows: 



1. Obtain a corrugated cardboard shipping carton 
having inside dimensions at least six inches greater 
than the instrument dimensions and having a carton 
test strength of at least 275 pounds. 



2. If the instrument is to be shipped to a Tektronix 
Service Center for service or repair, attach a tag to 
the instrument showing the following: owner of the 
instrument (with address), the name of a person at 
your firm who can be contacted, complete instru- 
ment type and serial number, and a description of the 
service required. 



2-2 



Preparation for Use— 2445 Operators 



3. Wrap the instrument with polyethylene sheeting or 
equivalent to protect the outside finish and prevent 
entry of packing materials into the instrument. 



5. Seal the carton with shipping tape or with an indus- 
trial stapler. 



4. Cushion the instrument on all sides by tightly packing 
dunnage or urethane foam between the carton and 
the instrument, allowing three inches on each side. 



6. Mark the address of the Tekronix Service Center and 
your return address on the carton in one or more 
prominent locations. 



Table 2-1 
Voltage, Fuse, and Power-Cord Data 



Plug 
Configuration 



Category 



Power Cord 

And 
Plug Type 



Line 
Voltage 
Selector 
Setting 



Voltage 

Range 

(AC) 



Factory 

Installed 

Instrument 

Fuse 



Fuse 

Holder 

Cap 



Reference 
Standards' 1 




U.S. 
Domestic 
Standard 



U.S. 
120V 
15A 



115V 



90V to 
132V 



2A, 250V 
AGC/3AG 

Fast-blow 
(UL 198.6) 



AGC/3AG 



ANSI C73.1 1 
NEMA5-15-P 
IEC83 
UL 198.6 




Option A1 



EURO 

240V 

10-1 6A 



230V 



1 80V to 
250V 



1.6A, 250V 
5x20 mm 

Slow-blow 
(IEC 127) 



5x20 mm 



CEE(7), II, IV, VII 
IEC 83 
IEC 127 




Option A2 



UK a 

240V 

6A 



230V 



180V to 
250V 



1 .6A, 250V 
5x20 mm 
Slow-blow 
(IEC 127) 



5x20 mm 



BS 1 363 
IEC 83 
IEC 127 




Option A3 



Australian 
240V 
10A 



230V 



1 80V to 
250V 



1.6A, 250V 
5x20 mm 
Slow-blow 
(IEC 127) 



5x20 mm 



AS C1 1 2 
IEC 127 




Option A4 



North 

American 

240V 

15A 



230V 



180V to 
250V 



2A, 250V 
AGC/3AG 
Slow-blow 
(UL 198.6) 



AGC/3AG 



ANSI C73.20 
NEMA6-15-P 
IEC 83 
UL 198.6 




Option A5 



Switzerland 

220V 

6A 



230V 



180V to 
250V 



1 .6A, 250V 
5x20 mm 
Slow-blow 
(IEC 127) 



5x20 mm 



SEV 
IEC 127 



a A 6A, Type C fuse is also installed inside the plug of the Option A2 power cord. 

b Reference Standards Abbreviations: 

ANSI— American National Standards Institute 
AS— Standards Association of Australia 
BS— British Standards Institution 
CEE— International Commission on Rules for 
the Approval of Electrical Equipment 



IEC — International Electrotechnical Commission 
NEMA— National Electrical Manufacturer's Association 
SEV— Schweizevischer Elektrotechischer Verein 
UL— Underwriters Laboratories Inc. 



(3832-02)3830-15 



REV JUL 1984 



2-3 



Section 3-2445 Operators 



CONTROLS, CONNECTORS, 
AND INDICATORS 



The following descriptions are intended to familiarize 
the operator with the location and function of the instru- 
ment's controls, connectors, and indicators. 



POWER AND DISPLAY 

Refer to Figure 3-1 for location of items 1 through 9. 

(T) INTENSITY Control -Adjusts brightness of the crt 
~ trace display. This control does not affect intensity of 
the crt readout display. 



Cl) BEAM FIND Switch-When held in, compresses the 
display to within the graticule area. Aids the operator 
in locating off-screen displays. 



(7) SCALE ILLUM Control-Adjusts the light level of 
the graticule illumination. 



POWER Switch-Turns instrument power on and off. 
Press in for ON; press again for OFF. An internal 
indicator in the switch shows green when the switch 
is on and black when it is off. Front-panel settings 
that were unchanged for at least 10 seconds prior to 
power-off will be returned when power is reapplied to 
the instrument. 



© 



CRT-Has an 80-mm vertical and 100-mm horizontal 
display area. Internal graticule lines eliminate parallax- 
viewing error between the trace and the graticule 
lines. Rise-time measurement points are indicated 
at the left edge of the graticule. 



(T) FOCUS Control-Adjusts the display for optimum 
definition. 



© 



© 



TRACE ROTATION Control-Operator-adjusted 
screwdriver control used to align the crt trace with 
the horizontal graticule lines. Once adjusted, it does 
not require readjustment during normal operation of 
the instrument. 



READOUT INTENSITY Control-Adjusts the inten- 
sity of the crt readout display. This control is also 
used to either enable or disable the scale-factor 
display. Setting the control to MIN reduces the 
readout intensity to minimum. Clockwise rotation 
from midrange increases the readout intensity and 
enables the scale-factor display; counterclockwise 
rotation from midrange also increases the intensity 
but disables the scale-factor display. Delta Volts and 
Delta Time readouts and control messages will 
continue to be enabled even when the scale-factor 
display is disabled. 



© 



ASTIG Control-Operator-adjusted screwdriver con- 
trol used in conjunction with the FOCUS control to 
obtain a well-defined display over the entire graticule 
area. Once adjusted, it does not require readjustment 
during normal operation of the instrument. 




FOCUS READOUT INTENSITY SCALE ILLUM 

HDTATIOd ^o^ *STIG 



D © ®..:0-.® 



Off | 



6©®©©®®© 



3830-04 



Figure 3-1. Power and display controls. 



3-1 



Controls, Connectors, and lndicators-2445 Operators 

VERTICAL 

Refer to Figure 3-2 for location of items 10 through 17. 



® 



® 



CH 1 OR X and CH 2 Input Connectors-Provide 

for application of external signals to the inputs of 
Channel 1 and Channel 2 vertical attenuators. A 
signal applied to the CH 1 OR X connector provides 
the horizontal deflection for an X-Y display. Any 
one or all of the channels (including Channel 1) 
may supply the signal for the X-Y display vertical 
deflection. These connectors each include a coding- 
ring contact that activates the scale-factor-switching 
circuitry whenever a scale-factor-switching probe 
is connected. The internal circuitry recognizes 
Tektronix attenuation-coded probes. 



Input Coupling Switches and Indicators-Select the 

method of coupling input signals to the Channel 1 
and Channel 2 vertical attenuators and indicate the 
selection made. If the Channel 1 and Channel 2 input 
signals are both AC coupled and if both input cou- 
pling switches are pushed up together, the instrument 
automatically performs a dc balance of Channel 1 
and Channel 2 vertical circuitry. 



1 MJ2 AC— Input signal is capacitively coupled to 
the vertical attenuator. The dc component of the 
input signal is blocked. The low-frequency limit 
(—3 dB point) is 10 Hz or less when using either 
a 1X probe or a coaxial cable and is 1 Hz or less 
when using a properly compensated 10X probe. 



1 M£2 GND-The input of the vertical amplifier 
is grounded to provide a zero (ground) reference- 
voltage display. Input resistance is 1 MJ2 to ground. 
This position of the switch allows precharging of 
the input-coupling capacitor to prevent a sudden 
shift of the trace if AC input coupling is selected 
later. 



1 MS2 DC— All frequency components of the input 
signal are coupled to the vertical attenuator. Input 
resistance is 1 MJ2 to ground. 



1 MD, GND— In this position, the switch operates 
exactly the same as previously described. 



50 £2 DC— All frequency components of the input 
signal are coupled to the vertical attenuator, with 
the input terminated by 50 £2 to ground. If exces- 
sive signal is applied to either the CH 1 or the 



CH 2 input connector while 50 £2 DC input 
coupling is selected, input coupling will revert to 
1 M£2 GND and a crt readout will indicate the 
overloaded condition. Moving the input coupling 
switch of the affected channel removes the over- 
load message. While power is off, coupling is at 
IMfiGND. 

(U) Channel 1 and Channel 2 VOLTS/DIV Switches- 
Select vertical deflection factor settings in a 1-2-5 
sequence with 1 1 positions. The VAR control must 
be in the detent (fully clockwise) position to obtain 
a calibrated deflection factor. Basic deflection factors 
are from 2 mV per division to 5 V per division. 
Deflection factors shown in the crt readout reflect 
actual deflection factors in use when Tektronix 
attenuation-coded probes are connected to the 
inputs. 

(13) VAR Controls— Provide continuously variable, un- 
calibrated deflection factors between the calibrated 
settings of the VOLTS/DIV switches. These controls 
vary the deflection factors from calibrated (fully 
clockwise detent position) to at least 2.5 times the 
calibrated deflection factor (fully counterclockwise 
position). When out of the calibrated detent, a greater 
than (>) sign appears in front of the associated 
VOLTS/DIV readout display. 




3832-05 



Figure 3-2. Vertical controls and CH 1 OR X and CH 2 connectors. 



3-2 



Controls, Connectors, and lndicators-2445 Operators 



(U) MODE Switches-Select the indicated channel(s) 
for display when latched in. Any combination of the 
five possible signal selections can be displayed by 
pressing in the appropriate push buttons. The Chan- 
nel 1 signal will be displayed if none of the MODE 
switches are latched in. 

The algebraic sum of Channel 1 and Channel 2 is 
displayed when the ADD push button is latched in. 
When both ADD and INVERT buttons are latched in, 
the waveform displayed is the difference between the 
Channel 1 and Channel 2 signals. The INVERT 
button also inverts the polarity of the signal output 
at the CH 2 SIG OUT connector on the rear panel. 
At the same time, the Channel 2 trigger-signal 
polarity is inverted so that if CH 2 is selected as the 
TRIGGER SOURCE, the displayed slope will agree 
with the TRIGGER SLOPE switch setting. 

When multiple channels are selected, they are dis- 
played sequentially in order of priority. The estab- 
lished priority order is: CH 1, CH 2, ADD, CH 3, 
then CH 4. 



The position of this switch has no effect on the 
switching rate of multiple X-Y displays. When more 
than one X-Y display is selected, switching occurs 
at 2.5 MHz. 



(j7) 20 MHz BW LIMIT Switch-Reduces upper 3dB 
bandpass of the vertical deflection system to a limit 
of 13 to 24 MHz when latched in. Full instrument 
bandwidth is available when push button is out. 



Refer to Figure 3-3 for location of items 18 through 22. 



® 



CH 3 and CH 4 Input Connectors-Provide for 
application of external signals to Channel 3 and 
Channel 4. Input coupling from these connectors is 
DC only. Coding-ring contacts, identical in operation 
to the CH 1 OR X and CH 2 input connectors, are 
also provided. Channel 3 and Channel 4 are most 
useful as digital signal and trigger signal input chan- 
nels, given their limited choice of deflection factors. 



(l5) POSITION Controls-Set vertical position of the 
Channel 1 and Channel 2 signal displays. Clockwise 
rotation of a control moves the associated trace 
upward. When the X-Y display feature is in use, 
Channel 1 POSITION control moves the display 
horizontally; clockwise moves it to the right. The 
Channel 2, Channel 3, and Channel 4 vertical POSI- 
TION controls move the associated X-Y display 
vertically. 



(J6) CHOP-OUT: ALT Switch -Selects the vertical display 
mode for multiple-channel displays. 



CHOP (latched in)-When more than one channel 
is selected, the vertical display switches sequen- 
tially through the selected channels at the chop- 
switching rate. 

The chop frequency changes between 1 MHz and 
2.5 MHz, depending on the SEC/DIV switch 
setting. At all sweep speeds, the chop-switching 
rate is desynchronized with the sweep frequency 
to minimize waveform breaks when viewing 
repetitive signals. 



OUT: ALT (released out)— When more than one 
channel is selected, the vertical display switches 
sequentially through the selected channels. Alter- 
nate switching occurs during sweep-retrace times. 
If both A and B Sweeps are displayed, alternate 
switching occurs at the completion of the B Sweep. 



(ji) POSITION Controls-Set vertical position of the 
Channel 3 and Channel 4 signal displays. The controls 
operate identically to the Channel 2 POSITION con- 
trol, but with less range on their associated traces. 



® 



Channel 3 and Channel 4 VOLTS/DIV Switches- 
Select either of two basic deflection factors for Chan- 
nel 3 and Channel 4. With the push button OUT, the 
basic deflection factor (using a 1X probe or a coaxial 
cable input connection) is 0.1 V per division; when it 
is latched IN, deflection factor is 0.5 V per division. 



<>POSITION VjLTS/JJV <>POSITION 




■® 



■® 



3832-06 



Figure 3-3. Channel 3 and Channel 4 controls and connectors and 
CALIBRATOR output. 



3-3 



Controls, Connectors, and lndicators-2445 Operators 



® 



CALIBRATOR Connector-Provides a 0.4-V p-p 
square-wave signal into a 1-Mfi load, a 0.2-V p-p 
square-wave signal into a 50-fZ dc-coupled load, or 
an 8-mA p-p square-wave current signal into a short 
circuit at a sweep speed of 1 ms per division. The 
CALIBRATOR output signal is useful for checking 
the sweep, the delays, and the vertical deflection 
accuracies, as well as compensating voltage probes 
and checking the accuracy of current probes. The 
repetition rate of the square wave changes with the 
setting of the A SEC/DIV switch. For all sweep-speed 
settings from 100 ms per division to 100 ns per 
division, the A Sweep display, as seen on the instru- 
ment supplying the CALIBRATOR signal, will be 
five cycles per 10 divisions. At 100 ms per division 
and slower, the CALIBRATOR frequency will be 
5 Hz; at 100 ns per division and faster, the frequency 
will be 5 MHz. The signal amplitude at 5 MHz will be 
at least 50% of the signal amplitude obtained when 
the sweep speed is set to 1 ms per division. 

NOTE 

Due to internal circuitry constraints, the 
calibrator signal is not synchronized during 
trace ho/doff. This does not affect the accuracy 
of the calibrator signal that is present during 
a trace display. However, if the 2445 CALI- 
BRATOR signal is used to calibrate other 
instruments, the sweep of the 2445 must be 
shut off. If it is not, the signal will appear to 
jitter and will give false (low) frequency counts 
The sweep of the 2445 is easily shut off by set- 
ting the TRIGGER MODE switch to SGL SEQ. 



(22) Auxiliary Ground Jack-Provides an auxiliary signal 
*~ ground when interconnecting equipment under test 

and the oscilloscope. Hookup is made via a banana-tip 

connector. 



HORIZONTAL AND 
DELTA MEASUREMENT 

Refer to Figure 3-4 for items 23 through 33. 



® 



® 



A SEC/DIV Switch-Selects 25 calibrated A Sweep 
speeds from 1 s per division to 10 ns per division, or 
delay ranges from 10 s to 200 ns, in a 1-2-5 sequence. 
Extreme counterclockwise switch rotation selects the 
X-Y display mode. In X-Y, the signal applied to the 
CH 1 OR X input connector drives the horizontal 
deflection system. 



B SEC/DIV Switch-Selects 21 calibrated B Sweep 
speeds from 50 ms per division to 10 ns per division 
in a 1-2-5 sequence. This switch also controls Hori- 
zontal Display Mode switching, as explained in the 
following descriptions. 



Knobs Locked-When both the A SEC/DIV and 
B SEC/DIV switches are set to the same sweep 
speed and the B SEC/DIV knob is pushed in, the 
two knobs are locked together; in this position, 
only the A Sweep is displayed on the crt. 



PULL-INTEN-Pulling the B SEC/DIV knob to the 
out position intensifies the A Sweep display for 
the duration of the B Sweep time. When both the 
A SEC/DIV and B SEC/DIV switches are set to the 
same sweep speed, the B Sweep is not displayed, 
but it runs at one of two speeds: either 100 times 
faster than the A Sweep speed or at 5 ns per 
division, whichever is slower. The A and B SEC/ 
DIV knobs are interlocked to prevent the B SEC/ 
DIV switch from ever being set to a slower sweep 
speed than the A SEC/DIV switch setting. 

The position of the intensified zone on the A 
Sweep indicates the delay time between the start 
of the A Sweep and start of the B Sweep interval. 
Its position is controlled by the A REF OR DLY 
POS control. 



For single-trace displays, when either the Delta 
Time (At) or the reciprocal Delta Time (1/At) 
function is activated, two intensified zones will 




3830-07 



Figure 3-4. Horizontal and delta measurement controls. 



3-4 



Controls, Connectors, and Indicators— 2445 Operators 



appear on the A Sweep if the B TRIGGER MODE 
is set to RUN AFT DLY. When the B TRIGGER 
MODE is set to TRIG AFT DLY, intensified zones 
appear on the A Sweep only if proper B Sweep 
triggering occurs before the end of the A Sweep. 
When set to RUN AFT DLY, the position of the 
Reference zone is controlled by the A REF OR 
DLY POS control as before, and the position of 
the Delta zone is controlled by the A control. In 
TRIG AFT DLY mode, if the B Sweep is triggered, 
the positions of both intensified zones are deter- 
mined by the first triggering events that occur 
after delay times set by the A REF OR DLY POS 
and the A controls have elapsed. 

When more than one trace is displayed using ALT 
VERT MODE, and if the A Sweep is being trig- 
gered from a single source, with the At or 1/At 
function selected, the Reference zone will appear 
on the first selected trace from the following 
sequence: CH 1, CH 2, ADD, CH 3, then CH 4. 
The Delta zone appears on the second selected 
trace, and both zones appear on any additional 
traces. With CHOP VERT MODE or multiple- 
channel triggering, both zones appear on all traces. 



Pulling the B SEC/DIV knob to the out position 
will cancel the Delta Volts (AV) function, if it is 
activated. Pushing in the B SEC/DIV knob to 
the locked position will cancel the NO AV WITH 
DELAY message on the crt readout, if it is being 
displayed. 



PULL-ADJ CH 2 DLY-When the A SEC/DIV 
switch is set to 10 ns per division, pulling the 
B SEC/DIV knob to the out position activates 
the Channel 2 delay-offset (CH 2 DLY) adjust- 
ment feature. See "Matching Channel 2 Delay" in 
Section 5, "Operator's Checks and Adjustments," 
to use this feature. 



TURN-ALT-Pulling the B SEC/DIV knob to the 
out position, then turning it to a faster sweep- 
speed setting than the A SEC/DIV sweep-speed 
setting, produces the Alternate (ALT) Horizontal 
Display Mode. The A Sweep with an intensified 
zone will be alternately displayed with the B 
Sweep, provided the B TRIGGER MODE is set 
either to RUN AFT DLY or to TRIG AFT DLY 
with a proper B triggering signal occurring before 
the end of the A Sweep. The position of the 
intensified zone on the A Sweep indicates the 
approximate delay of the B Sweep, and the length 
of the intensified zone indicates the approximate 
B Sweep duration set by the B SEC/DIV switch. 



If either At or 1/At is also activated, intensified 
zones and associated B Sweeps will be established 
in the same manner as described in "PULL- 
INTEN." 



PUSH-B-Pushing in the B SEC/DIV knob when 
the B SEC/DIV switch is set to a faster sweep 
speed than the A SEC/DIV switch presents only 
the B Sweep trace(s) on the crt display. 

(25) SEC/DIV VAR Control-Continuously varies the 
"* sweep speed between settings of either the A or the 
B SEC/DIV switch. This control affects the A Sweep 
speed when the A and B SEC/DIV switches are 
locked together. When any of the delayed-sweep 
horizontal modes are displayed, the control affects 
only the B Sweep speed. 



Fully counterclockwise rotation extends the sweep 
speed of the slowest A SEC/DIV switch setting 
(1 s per division) to 1.5 s per division. Fully clock- 
wise rotation (detent position) produces the sweep 
speed indicated by the position of the SEC/DIV 
switches. The crt readout displays the actual time- 
per-division scale factor for all settings of the VAR 
control. 



This control produces fine resolution over a portion 
of its range, after which it changes to coarse reso- 
lution. It reenters the fine-resolution range upon 
reversing the direction of rotation. 

(26) TRACE SEP Control -Provides for vertical position- 
~ ing of the B trace downward from the A trace when 
TURN-ALT Horizontal Display Mode is selected. 
Counterclockwise rotation moves the B trace down- 
ward. At the fully clockwise stop position of the 
control, there is no separation between the A and B 
traces. When the PUSH-B Horizontal Display Mode 
is selected and when either At or 1/At measurement 
mode is active, the TRACE SEP control provides for 
vertical positioning of the trace or traces associated 
with the A control. 



© 



Horizontal POSITION Control-Sets the horizontal 
position of the sweep displays on the crt. Clockwise 
rotation of the control positions the display to the 
right. This control produces fine resolution over a 
portion of its range, after which it changes to coarse 
resolution. It reenters the fine-resolution range upon 
reversing the direction of rotation. The Horizontal 
POSITION control does not affect the X-Y display 
position on the crt. 



3-5 



Controls, Connectors, and lndicators-2445 Operators 



(28) X10 MAG Switch-Horizontally magnifies the por- 
tion of the sweep display positioned at the center 
vertical graticule line by a factor of 10 when pressed 
in. When the A trace and the B trace are displayed 
alternately {TURN-ALT Horizontal Display Mode 
selected), only the B trace is magnified. Using X10 
magnification extends the fastest sweep speed to 1 ns 
per division. The push button must be pressed in a 
second time to release it and regain the X1 sweep- 
speed magnification. 

(29) AV Switch-Activates the Delta Volts (AV) measure- 
ment function, when momentarily pressed in alone, 
and cancels any other Delta measurement function 
in effect. In the A Sweep mode (A and B SEC/DIV 
switches locked together), two horizontal cursors 
are superimposed on the crt display. The crt readout 
displays the equivalent voltage represented by the 
separation between the two cursors. The position of 
one cursor on the display is set by the A REF OR 
DLY POS control and the position of the other is 
set by the A control. With multiple-channel displays, 
the deflection factor of the first channel selected in 
the display sequence determines the scale factor of 
the Delta Volts readout on the crt. The Delta Volts 
readout is displayed as a percentage ratio if either one 
of the following conditions exists: (1)the channel 
determining the scale factor is uncalibrated (VAR 
control out of detent), or (2) ADD is displayed alone 
when the Channel 1 and Channel 2 deflection factors 
are not the same (VOLTS/DIV switches are at dif- 
ferent settings or are uncalibrated). Either pressing in 
the AV switch or pulling the B SEC/DIV knob to 
the out position when the Delta Volts function is 
active, cancels it. Attempting to activate the Delta 
Volts function while the A and B SEC/DIV knobs 
are unlocked causes the message NO AV WITH 
DELAY to appear in the top row of the crt readout. 
If displayed, the error message will be canceled 
(removed from the display) by any of the following 
actions: pressing either the AV or At switch; pushing 
in the B SEC/DIV if it is out or pulling it out if it is 
in; or locking the A and B SEC/DIV knobs together 
(set to the same sweep speed with the B SEC/DIV 
knob in). 



30) At Switch -Activates the Delta Time measurement 
function and cancels any other Delta measurements 
in effect, when momentarily pressed in alone. When 
the Delta Time function is active, momentarily 
pressing in the At push button cancels the function. 



two separate delay times are established by the 
Delta Time function. One cursor position (or delay 
time) is set by the A REF OR DLY POS control, 
and the other is set by the A control. The crt readout 
displays either the time difference between the two 
delays or the equivalent time difference between the 
two vertical cursors. 

If the SEC/DIV VAR control is not in the detent 
position, At cursor difference on the A trace only 
displays is expressed as a ratio, with five divisions 
corresponding to a 100% ratio. For the delay-time 
Horizontal Display modes, the SEC/DIV VAR 
control varies the B-sweep scale factor as it is rotated, 
but it has no effect on the delay time. 



Pressing in the AV and At push buttons together 
activates the 1/At measurement function and cancels 
any other Delta measurement functions in effect. The 
crt waveform display and operation of both the A 
REF OR DLY POS and A controls remain the same 
as explained for At operation. However, with 1/At 
selected, the crt readout shows the reciprocal of the 
time-difference measurement, with units being 
frequency (Hz, kHz, MHz, or GHz). 

For A trace only displays, with the SEC/DIV VAR 
control out of the detent (fully clockwise) position, 
the time difference between 1/At cursors is displayed 
in degrees of phase, with five divisions equal to 360 
degrees. As with At measurements, the position of 
the SEC/DIV VAR control has no effect on delay- 
time displays except to change the B Sweep scale 
factor, and the readout remains in units of frequency. 



When the 1/At function is active, pressing both the 
AV and the At push buttons together cancels the 
function and exits the Delta measurement mode. 
Pressing either AV or At alone cancels the 1/At 
function and activates the function associated with 
the button pressed. 



(3l) A REF OR DLY POS Control-Sets the reference B 
Sweep delay time or positions the Reference cursor 
when AV, At, or 1/At Measurement Mode is active. 
When any delay-time Horizontal Display Mode 
(PULL-INTEN, TURN-ALT, or PUSH-B) is selected, 
the reference B Sweep delay time is determined by 
the rotation of the A REF OR DLY POS control in 
conjunction with the A SEC/DIV switch setting. 



When the A and B SEC/DIV knobs are locked together 
(A trace only), two vertical cursors are superimposed 
on the crt display while the Delta Time function is 
active. In any of the delay-time Horizontal Display 
modes (PULL-INTEN, TURN-ALT, or PUSH-B), 



This control produces fine resolution over a portion 
of its range, after which it changes to coarse reso- 
lution. It reenters the fine-resolution range upon 
reversing the direction of rotation. 



3-6 



Controls, Connectors, and Indicators— 2445 Operators 



(32) A Control-Sets the alternate B Sweep delay time or 
positions the Delta-time cursor (vertical line) when 
either the At or 1/At Measurement Mode is active. 
When the AV Measurement Mode is active (A Sweep 
Horizontal Display Mode only), the control positions 
one of the two horizontal voltage cursors that appear 
on the crt display. 



This control produces fine resolution over a portion 
of its range, after which it changes to coarse reso- 
lution. It reenters the fine-resolution range upon 
reversing the direction of rotation. 



peak-reference levels and the trigger level are 
redefined whenever triggering ceases, whenever the 
LEVEL control is turned to either extreme, or 
when the MODE switch is pushed up. If the 
LEVEL control is set near either end position, the 
trigger level set by AUTO LVL will be near the 
corresponding signal peak. If the LEVEL control is 
set in the midrange between either end, the trigger 
level set by AUTO LVL will be near the midpoint 
of the trigger signal amplitude. The established 
trigger level remains in effect when switching 
to AUTO or NORM Trigger MODE unless the 
LEVEL control is moved. 



® 



TRACKING-OUT: INDEP Switch-Selects either the 
TRACKING or INDEP (independent) mode for the 
A REF OR DLY POS control. When in the TRACK- 
ING mode (push button latched in), the difference 
between alternate delay times or cursors (in either 
time or volts Measurement Mode) does not change 
with rotation of the A REF OR DLY POS control. 
When the A REF OR DLY POS control is rotated, 
the positions of both delays or of both cursors move 
equally until the limit of either is reached. 



If VERT TRIGGER SOURCE is selected, the 
lowest-numbered displayed channel (or the 
algebraic sum of Channel 1 and Channel 2 if ADD 
vertical display is selected) becomes the trigger- 
signal source. If Trigger MODE is changed from 
AUTO LVL to AUTO while more than one 
channel is displayed, the single-channel trigger 
source is retained, and the VERT SOURCE 
indicator is turned off. To regain the VERT 
TRIGGER SOURCE, press up momentarily on 
the SOURCE switch. 



If OUT: INDEP is selected (push button released), 
the cursors (or delay positions) are independently 
movable using the A REF OR DLY POS and A 
controls. In either mode (TRACKING or INDEP) 
the Delta cursor remains independently movable 
using the A control. 



TRIGGER 



Refer to Figure 3-5 for items 34 through 42. 



AUTO— Sweep free runs in the absence of a 
triggering signal. The triggering level changes only 
when the LEVEL control is adjusted to a new 
position. 



NORM— Sweep is triggered and runs when a 
triggering signal compatible with the LEVEL 
setting is applied. Sweep free runs either when the 
input coupling of the selected trigger SOURCE is 



® 



MODE Switch and Indicators-Selects the trigger 
mode of either the A Sweep or the B Sweep. A single 
push of the switch steps the MODE selection once; 
holding the switch up or down causes the MODE 
selection to step repeatedly. Indicators show the 
selected trigger mode of either the A Sweep or the 
B Sweep according to the selected Horizontal Display 
Mode and as directed by the A/B TRIG switch. 



A Trigger Modes: 

AUTO LVL— Automatically establishes the trigger 
level on a triggering signal and free runs the sweep 
in the absence of a triggering signal. The LEVEL 
control covers a range between the positive and 
negative peaks of repetitive triggering signals. If 
the triggering signal amplitude changes, the trigger 
level does not change unless a trigger is no longer 
produced at the established level. The signal 



® 




3832-08 



Figure 3-5. Trigger controls and indicators. 



3-7 



Controls, Connectors, and Indicators— 2445 Operators 



set to GND or when the input coupling of both 
Channel 1 and Channel 2 is set to GND, with 
ADD VERTICAL MODE and VERT TRIGGER 
SOURCE selected. 



SGL SEQ-When armed by pushing the MODE 
switch down momentarily, the sweep runs one or 
more times to produce a single sweep of each of 
the traces defined by the following controls: 
VERTICAL MODE, A and B SEC/DIV, and At. 
Each sweep requires a distinct A Sweep triggering 
event. The READY indicator remains illuminated 
until the final trace in the sequence is completed. 
At the end of the sequence the crt readout is 
written once to present scale factors and other 
readout data, and scale illumination flashes on 
momentarily for oscilloscope photography 
purposes. 



B Trigger Modes: 

RUN AFT DLY-The B Sweep runs immediately 
after the established delay time has elapsed. 
Delay time is set by the A SEC/DIV switch and 
the A POS OR DLY REF control when no Delta 
Time measurements are selected (neither At nor 
1/At). 

When either At or 1/At measurements are made, 
two delay times are established: one by the A 
REF OR DLY POS control and the other by the 
A control. 



TRIG AFT DLY-The B Sweep runs when trig- 
gered by a triggering signal after the established 
delay time has elapsed, provided the A Sweep has 
not terminated. Since the B Sweep runs at the 
time the triggering signal occurs, the display is 
stable, even with jittering signals; but the actual 
delay time is greater than the delay-time setting. 
Therefore, the crt readout shows a question mark 
in this mode. 



When ALT VERTICAL MODE is selected, each 
displayed channel in turn provides the triggering 
signal, and the respective LED indicator for each 
displayed channel is illuminated, except in the case 
of AUTO LVL MODE triggering. For AUTO LVL 
triggering or CHOP VERTICAL MODE, the lowest 
numbered channel, or ADD if it is displayed, is the 
triggering-signal source. The LED indicator for the 
lowest numbered channel displayed is illuminated, 
except if ADD is selected. Then, the CH 1, CH 2, 
and VERT indicators are illuminated. 

CH 1, CH 2, CH 3, or CH 4-A triggering signal is 
obtained from the corresponding vertical channel. 

LINE (A Trigger Only)-A triggering signal is 
obtained from a sample of the ac power-source 
waveform. This trigger source is useful when 
vertical input signals are time related (multiple or 
submultiple) to the frequency of the ac power- 
source voltage. 



(3B) COUPLING Switch and Indicators-Selects the 
method of coupling the triggering signal to the A and 
the B trigger generator circuitry. A single push of the 
switch steps the COUPLING selection once; holding 
the switch up or down causes the COUPLING selec- 
tion to step repeatedly. Indicators show the coupling 
method selected for either the A triggering signals 
(when an A TRIGGER MODE is in effect) or the B 
triggering signals when TRIG AFT DLY is selected 
for the B TRIGGER MODE. Indicators do not 
illuminate for B triggering signals when RUN AFT 
DLY is selected. 



DC— All frequency components of the signal are 
coupled to the trigger-generator circuitry. This 
coupling method is useful for triggering on most 

signals. 



® 



SOURCE Switch and Indicators— Selects the trigger 
signal source for either the A or the B Sweep. 
Indicators show the selection made. A single push of 
the switch steps the SOURCE selection once; holding 
the switch up or down causes the SOURCE selection 
to step repeatedly. Indicators do not illuminate for 
B triggering signals when RUN AFT DLY is selected. 



NOISE REJ— All frequency components of the 
input signal are coupled to the trigger-generator 
circuitry, but the peak-to-peak signal amplitude 
required to produce a trigger event is increased. 
This coupling method is useful for improving 
trigger stability on signals accompanied by low- 
level noise. 



VERT— The sweep triggers on the displayed 
channel when only one channel is selected. If 
multiple vertical displays are selected, both the 
Trigger MODE in use and position of the CHOP/ 
ALT button affect the trigger-source selection. 



HF REJ— Attenuates high-frequency triggering- 
signal components above 50 kHz. This coupling 
method is useful for eliminating radio-frequency 
interference and high-frequency noise components 

from the signal applied to the trigger-generator 



3-8 



Controls, Connectors, and Indicators— 2445 Operators 



circuitry; it allows stable triggering on the low- 
frequency components of a complex waveform. 



LF REJ— Signals are capacitively coupled, and the 
dc component of the triggering signal is blocked. 
Attenuates the low-frequency signal components 
below 50 kHz. This coupling method is useful for 
producing stable triggering on the high-frequency 
components of a complex waveform. Low- 
frequency components such as power-supply hum 
are removed from the signal applied to the trigger- 
generator circuitry. 



AC— Signals are capacitively coupled. Frequency 
components below 60 Hz are attenuated, and the 
dc component of the input signal is blocked. This 
coupling method is useful for signals that are 
superimposed on slowly changing dc voltages. 
This method will work for most signals when 
trigger-level readout is not desired. 



(37) A/B TRIG Switch-Directs the MODE, SOURCE, 
COUPLING, SLOPE, and LEVEL controls to either 
the A Trigger or the B Trigger, under the allowed 
switching conditions. Controls are normally directed 
to the A Trigger when the A and B SEC/DIV knobs 
are locked together (A Sweep display only). Controls 
are normally directed to the B Trigger when the 
B TRIGGER MODE is set to TRIG AFT DLY and 
the A and B SEC/DIV knobs are unlocked (PULL- 
INTEN, TURN-ALT, or PUSH-B Horizontal Display 
Mode). Pressing and holding in the A/B TRIG switch 
will direct the trigger controls away from their 
normal trigger direction, but releasing the A/B TRIG 
switch will redirect the trigger controls back to the 
original triggers. 



If the A and B SEC/DIV knobs are unlocked and 
either the B TRIGGER MODE is set to RUN AFT 
DLY or the A TRIGGER MODE is set to SGL SEQ, 
the A/B TRIG switch will direct the trigger controls 
to the opposite trigger each time it is momentarily 
pressed and released. 



® 



LEVEL Control— Sets the amplitude point on the 
triggering signal at which either A or B Sweep trig- 
gering occurs. This control produces fine resolution 
for a portion of its range, after which it changes to 
coarse resolution. It reenters the fine-resolution range 
upon reversing the direction of rotation. 

When the A TRIGGER MODE is set to AUTO LVL, 
the effect of the LEVEL control is spread over the 
A Sweep triggering-signal amplitude from peak to 
peak. In this case, rotating the control to either 
extreme causes the triggering level to be redefined 
by the AUTO LVL circuitry. 

SLOPE Switch and Indicators— Selects the slope of 
the signal that triggers either the A Sweep or the 
B Sweep. Indicators illuminate to show slope selec- 
tion made for the A Sweep and for TRIG AFT DLY 
B Sweeps. The + and — indicators do not illuminate 
for B triggering when RUN AFT DLY is selected. 



40) A SWP TRIG'D Indicator-Illuminates to indicate 
that the A Sweep is triggered. It extinguishes after 
a nominal length of time when a triggering signal is 
not received following completion of the sweep. 



® 



® 



® 



READY Indicator-Illuminates when SGL SEQ 
MODE is selected and the A Sweep is armed and 
waiting for a triggering event to occur. It extinguishes 
following the completion of all the traces selected 
for the SGL SEQ display. 



HOLDOFF Control-Varies the amount of holdoff 
time between the end of the sweep and the time a 
triggering signal can initiate the next sweep. The 
ability to obtain stable triggering on some aperiodic 
signals is improved using this control. In the B ENDS 
A position (fully clockwise) trigger holdoff time is 
reduced to minimum, and the A Sweep terminates 
immediately at the end of the B Sweep. This enables 
the fastest possible sweep-repetition rate at slow A 
Sweep speeds. 



Locking the A and B SEC/DIV knobs together will 
switch the trigger controls to the A Trigger if they 
are currently directed to the B Trigger. Pulling the 
B SEC/DIV knob to the out position will cause the 
trigger controls to revert to the B Trigger if the B 
TRIGGER MODE is set to TRIG AFT DLY. How- 
ever, if the B TRIGGER MODE is set to RUN AFT 
DLY when the B SEC/DIV knob is unlocked from 
the A SEC/DIV knob, the trigger controls remain 
directed to the A Trigger until the B Trigger is 
reselected by the A/B TRIG switch. 



REAR PANEL 

Refer to Figure 3-6 for location of items 43 through 49. 

(43) A GATE OUT and B GATE OUT Connectors- 
Provide TTL-compatible, positive-going gate signals 
that are HI during their respective sweeps and LO 
while the sweep is not running. 



3-9 



Controls, Connectors, and Indicators— 2445 Operators 



(44) CH 2 SIGNAL OUT Connector-Provides an output 
signal that is a normalized representation of the 
Channel 2 input signal. The output amplitude into a 
1-Mf2 load is approximately 20 mV per division 
of input signal. Into a 50-£2 load, the output ampli- 
tude is approximately 10 mV per division of input 
signal. 



(45) EXT Z-AXIS IN Connector— Provides an input con- 
nection point to apply external Z-axis modulation 
signals to the Z-Axis Amplifier. Either the sweep or 
the X-Y display may be intensity modulated. Positive- 
going signals decrease the intensity. From dc to 
2 MHz, an input-signal amplitude of +2 V will blank 
a maximum-intensity trace; from 2 MHz to 20 MHz, 
an input-signal amplitude of +2 V will produce 
noticeable modulation on a normal-intensity trace. 



(46) Fuse Holder— Contains the ac power-source fuse. 



(47) Detachable Power Cord Receptacle— Provides the 
connection point for the ac power source to the 
instrument. 



® 



LINE VOLTAGE SELECTOR Switch-Selects the 
nominal instrument operating voltage range. When 
set to 115V, the instrument operates from a power- 
source voltage having a range of 90 V to 132 V ac. 
Set to 230V, the instrument operates on an input- 
voltage range of 180 V to 250 V ac. 



Modulating signals with fast rise and fall times produce 
the most abrupt intensity changes. External Z-axis 
signals must be time related to the displayed signal 
frequency to obtain a stable intensity-modulation 
pattern on the crt. 



(49) Mod Slots— Contain the identification numbers of any 
"~" installed instrument modifications. 




cAimos 



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^h** 1 r mm 



16A^ 



PCWiR MM Wiio "£) ' 

MAX W I9C 
flttO 4M4Mb 







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3830-09 



Figure 3-6. Rear-panel controls and connectors. 



3-10 



Controls, Connectors, and Indicators— 2445 Operators 



READOUT DISPLAY 

The Readout System provides an alphanumeric display 
of information on the crt along with the analog waveform 
display. The readout is displayed in two rows of 32 char- 
acters each. One row is within the top graticule division, 
and the other row is within the bottom graticule division. 
The locations and types of information displayed under 
normal operating modes are illustrated in Figure 3-7. 



The Trigger-Level readout shows the signal voltage 
(at the probe tip of encoded probes) that will initiate 
the sweep. The readout appears only if the following con- 
ditions exist: a single vertical channel is selected as the 
trigger source, the vertical input coupling is not AC, the 
VOLTS/DIV VAR control of the source channel is in the 
calibrated detent, and trigger coupling is either DC or 
NOISE REJ. 



NOTE 

Other information is displayed when the instrument 
is in a diagnostic mode or has experienced a fault. If 
the normally blank spaces of the bottom row of the 
display are filled with dots, refer the instrument to a 
qualified service person for recalibration. 



Each of the scale-factor displays appears when the 
respective vertical channel or sweep is displayed. When X-Y 
mode is selected, the Channel 1 scale factor is displayed, 
and CH 1 X appears in place of the A Sweep scale factor. 



A question mark may appear in a DLY (delay time), a 
At (delta time), or a 1/At readout when the SEC/DIV 
knobs are unlocked (not with cursors). This indicates that 
either the delay time (or one of the two delay times) is set 
at less than 0.5% of the maximum delay or the B TRIG- 
GER MODE is set to TRIG AFT DLY. A question mark 
will also appear in a 1/At display readout when the 
difference between the two delays (or the distance between 
the two cursors displayed when the A and B SEC/DIV 
knobs are locked together) is less than 1% of full scale. 



Special characters or abbreviations are displayed to 
indicate GND or AC coupling of Channel 1 or Channel 2 
signals, ADD, CH 2 INVERT, Vertical bandwidth limited, 
or HOLDOFF not set to minimum. 



The 50 £1 OVERLOAD display appears if excessive signal 
is applied to either the CH 1 or the CH 2 input connector 
while 50 SI DC input coupling is selected. The readout will 
return to the normal display when the input coupling of the 
overloaded channel is switched. 



TRIGGER LEVEL INDICATOR 



50 n OVERLOAD 
INDICATION 



TRIGGER SOURCE 
(1,2, 3, OR 4) 



TRIGGER CURRENTLY UNDER 
CONTROL (A OR B) 



ADD INDICATOR (+) 



CHANNEL 1 
SCALE FACTOR 




SWEEP DELAY TIME 

DELTA VOLTAGE 

DELTA TIME 

1/DELTA TIME 



INVERT INDICATOR (I) 



CHANNEL 2 
SCALE FACTOR 



BANDWIDTH 

LIMIT INDICATOR 

(BWL) 



HOLDOFF INDICATOR (HO) 



B SWEEP SCALE FACTOR 



A SWEEP SCALE FACTOR 



CHANNEL 4 SCALE FACTOR 



CHANNEL 3 
SCALE FACTOR 



3832-10 



Figure 3-7. Readout display locations. 



3-11 



Section 4—2445 Operators 



OPERATING CONSIDERATIONS 



This section contains basic operating information and 
techniques that should be considered before attempting 
to make any measurements with your instrument. 



GRATICULE 



TIME AND VOLTAGE 
MEASUREMENTS 

The 2445 provides three basic ways to make time 
measurements and two basic ways to make voltage measure- 
ments. These methods require varying degrees of time and 
care and can result in varying degrees of accuracy. 



The graticule is internally marked on the faceplate of 
the crt to eliminate parallax-viewing error and to enable 
accurate measurements (see Figure 4-1). It is marked with 
eight vertical and ten horizontal major divisions. In addition, 
each major division is divided into five subdivisions. The 
vertical deflection factors and horizontal timing are cali- 
brated to the graticule so that accurate measurements 
can be made directly from the crt. Also, percentage marks 
for the measurement of rise and fall times are located on 
the left side of the graticule. 



1ST OR LEFT 

VERTICAL 

GRATICULE 

LINE 



11TH OR RIGHT 

VERTICAL 

GRATICULE 

LINE 








| 


| 












I : 


; 














* 










- 




: 










- 




I 










- 




E 










- 




E 














z 












z ; 












E i 









7 



RISE AND 

FALL TIME 

MEASUREMENT 

PERCENTAGE 

MARKERS 



CENTER 

VERTICAL 

GRATICULE 

LINE 



CENTER 

HORIZONTAL 

GRATICULE 

LINE 



4207-09 



Using graticule markings for determining voltage or time 
values produces the least accurate measurement values. 
This method should be used only for measuring very-low- 
repetition-rate signals or for single-shot measurements 
which require a photograph for viewing. 



The At and AV cursors provide for better accuracy and 
easier operation than using the graticule, and they should 
be used in most measurement situations. Use of the cursors 
avoids vertical- and horizontal-gain errors and crt-linearity 
errors. Cursors also eliminate the inconvenience of counting 
and interpolating graticule markings. 



The Delayed Sweep mode provides the highest accuracy 
for making time measurements. This method avoids errors 
introduced either by visual-resolution limits or by slight 
mismatches between the sweep and the cursors. 



More details relating to various measurement techniques 
are contained in Section 6, "Basic Applications." 



Figure 4-1. Graticule measurement markings. 



GROUNDING 



The most reliable signal measurements are made when 
the 2445 and the unit under test are connected by a com- 
mon reference (ground lead) in addition to the signal 
lead or probe. The probe's ground lead provides the best 
grounding method for signal interconnection and ensures 
the maximum amount of signal-lead shielding in the probe 
cable. A separate ground lead can also be connected from 
the unit under test to the oscilloscope ground receptacle on 
the front panel. 



4-1 



Operating Considerations-2445 Operators 

SIGNAL CONNECTIONS 

Probes 

Generally, probes offer the most convenient means of 
connecting an input signal to the instrument. Shielded 
to prevent pickup of electromagnetic interference, the 
standard 10X probes supplied with this instrument offer 
a high input impedance that minimizes circuit loading. This 
allows the circuit under test to operate with a minimum of 
change from the normal, unloaded condition. Also, the 
subminiature body of these probes has been designed for 
ease of use either when probing circuitry containing close 
lead spacing or when probing in a confined space. 



Both the probe itself and the probe accessories should 
be handled carefully at all times to prevent damage. Avoid 
dropping the probe body. Striking a hard surface can cause 
damage to both the probe body and the probe tip. Exercise 
care to prevent the cable from being crushed or kinked. 
Do not place excessive strain on the cable by pulling. 



The standard-accessory probe is a compensated 10X 
voltage divider. It is a resistive voltage divider for low 
frequencies and a capacitive voltage divider for high- 
frequency signal components. Inductance introduced by 
either a long signal or ground lead forms a series-resonant 
circuit. This circuit will affect system bandwidth and will 
ring if driven by a signal containing significant frequency 
components at or near the circuit's resonant frequency. 
Oscillations (ringing) can then appear on the oscilloscope 
display and distort the true signal waveform. Always keep 
both the ground lead and the probe signal-input connec- 
tions as short as possible to maintain the best waveform 
fidelity. 



Misadjustment of probe compensation is a common 
source of measurement error. Due to variations in oscillo- 
scope input characteristics, probe compensation should 
be checked and adjusted, if necessary, whenever the probe 
is moved from one oscilloscope to another or between 
channels of a multichannel oscilloscope. See the procedure 
in Section 5, "Operator's Checks and Adjustments," or 
consult the probe instruction manual. 



Coaxial Cables 

Cables may also be used to connect signals to the input 
connectors, but they may have considerable effect on the 
accuracy of a displayed waveform. To maintain the original 



frequency characteristics of an applied signal, only high- 
quality, low-loss coaxial cables should be used. Coaxial 
cables should be terminated at both ends in their char- 
acteristic impedance. If this is not possible, use suitable 
impedance-matching devices. 



INPUT-COUPLING CAPACITOR 
PRECHARGING 

When the input coupling switch is set to GND, the input 
signal is connected to ground through the input-coupling 
capacitor in series with a 1-MS2 resistor to form a pre- 
charging network. This network allows the input-coupling 
capacitor to charge to the average dc voltage level of the 
signal applied to the probe. Thus, any large voltage tran- 
sients that may accidentally be generated will not be 
applied to the amplifier input when input coupling is 
switched from GND to AC. The precharging network also 
provides a measure of protection to the external circuitry 
by reducing the current levels that can be drawn from the 
external circuitry during capacitor charging. 



EXTERNAL TRIGGERING 

Both the A and the B trigger signals may be independ- 
ently obtained from any of the four vertical input channels. 
When viewing signals that require a trigger source different 
from one of the displayed vertical signals (traditionally 
referred to as "external triggering"), any free vertical 
channel may be used to input a trigger signal. The signal 
can be viewed on the crt to aid in setting the trigger circuit 
controls by selecting that respective channel for the vertical 
display (replaces the usual "trigger view" feature). After 
establishing the correct triggering, the trigger signal display 
can then be removed from the vertical signal display or 
allowed to remain, at the operator's descretion. 



Channel 1 and Channel 2 can condition a wide range of 
signals to produce triggers— over the full vertical deflection 
range of the channel from millivolts to hundreds of volts 
in amplitude. Channel 3 and Channel 4 inputs have a much 
more limited choice of vertical deflection ranges available 
(0.1 volt and 0.5 volt per division without external attenu- 
ation) and are more useful for digital signal amplitudes. 
However, signals much larger can be processed, provided 
they do not exceed the maximum-rated signal amplitude 
for the input. 



4-2 



Section 5-2445 Operators 



OPERATOR'S CHECKS 
AND ADJUSTMENTS 



INTRODUCTION 



To verify the operation and accuracy of your instru- 
ment before making measurements, perform the following 
check and adjustment procedures. If adjustments are 
required beyond the scope of these operator's checks 
and adjustments, refer the instrument to a qualified service 
technician. 



Before proceeding with these instructions, refer to 
"Preparation for Use" (Section 2). 



Verify that the POWER switch is OFF (push button 
out), then plug the power cord into the power outlet. 



If indications specified in these procedures cannot be 
obtained, refer the instrument to a qualified service 
technician. 



Horizontal 




AANDBSEC/DIV 


Locked together at 1 ms 


SEC/DIVVAR 


Calibrated detent 


POSITION 


Midrange 


1 0X MAG 


Off (button out) 


Trigger 




HOLDOFF 


Fully counterclockwise 


LEVEL 


Midrange 


MODE 


AUTO LVL 


SOURCE 


VERT 


COUPLING 


DC 


SLOPE 


+ 



3. Adjust the INTENSITY and READOUT INTENSITY 
controls for desired display and readout brightness and best 
trace definition. 



4. Adjust the Vertical and Horizontal POSITION 
controls to position the trace within the graticule area. 



INITIAL SETUP 

1. Press in the POWER switch button (ON) and allow 
the instrument to warm up (20 minutes is recommended 
for maximum accuracy). 



TRACE ROTATION ADJUSTMENT 



1. Preset instrument controls and obtain a baseline trace 
as described in "Initial Setup." 



2. Set instrument controls to obtain a baseline trace: 



Display 




READOUT 




INTENSITY 


Midrange between "MIN" 




and fully clockwise 


FOCUS 


Midrange 


Vertical 




POSITION 


Midrange 


MODE 


CH 1 


BW LIMIT 


Off (button out) 


CH 1 VOLTS/DIV 


10 mV 


CH 1 Input Coupling 


1 MfiGND 



2. Use the Channel 1 POSITION control to move the 
baseline trace to the center horizontal graticule line. 



NOTE 

Normally, the resulting trace will be parallel to the 
center horizontal graticule line, and the Trace Rota- 
tion adjustment should not be required. 



3. If the trace is not parallel to the center horizontal 
graticule line, use a small-bladed screwdriver to adjust the 
TRACE ROTATION control (see Figure 3-1) and align the 
trace with the center horizontal graticule line. 



5-1 



Operator's Checks and Adjustments-2445 Operators 

ASTIGMATISM ADJUSTMENT 

1. Preset instrument controls and obtain a baseline 
trace as described in "Initial Setup." Set 20 MHz BW 
LIMIT On (in) 



2. Connect a 10X probe to the CH 1 OR X input 
connector and connect the probe tip to the CALIBRATOR 
output. 



3. Adjust the Channel 1 POSITION control to center 
the display on the screen. 



4. Set A and B SEC/DIV controls at 1 p.s. 



operation are within nominal limits. The dc balance 
attained by the Auto DC Balance adjustment remains 
valid as long as the instrument is operating within 5°C of 
the ambient temperature at which the adjustment was 
performed provided a 20-minute warm-up period is allowed 
before performing the adjustment. To initiate the adjust- 
ment, set both the Channel 1 and Channel 2 input coupling 
switches to AC. Then simultaneously push up on both 
switches. An alternate method of entering the auto- 
adjustment mode is possible with only one of the input 
coupling switches set to AC. Press up and hold the input 
coupling switch that is not set to AC, then press up the 
other input coupling switch. With either method, the 
instrument will enter an auto-adjustment mode for about 
ten seconds. When the Auto DC Balance adjustment cycle 
is complete, the instrument will return to the normal 
operating mode. 



5. Slowly adjust the FOCUS control to its optimum 
setting (best-defined display). 



NOTE 

If the ASTIG adjustment is correctly set already, 
all portions of the trace will come into sharpest focus 
at the same position of the FOCUS control. 



6. If focusing is not uniform over the entire graticule 
area, use a small-bladed screwdriver to adjust the ASTIG 
control (see Figure 3-1). 



NOTE 

If a circuit defect prevents accurate dc balance, the 
routine halts and LIMIT is displayed. Push the Trigger 
COUPLING switch up to continue balancing the 
remainder of the circuitry. 

If power to the instrument is interrupted before the 
balancing cycle is completed, an error will be detected 
by the next power-on self test. Press A/B TRIG to 
exit the diagnostic monitor and restart the Auto 
DC Balance adjustment to allow the cycle to be 
completed. 



7. Since the ASTIG and FOCUS adjustments interact, 
repeat steps 5 and 6 until the best-defined display over the 
entire graticule area is obtained. 



PROBE LOW-FREQUENCY 
COMPENSATION 



NOTE 

Once it is set, the ASTIG adjustment should be 
correct for any display. However, it may be necessary 
to reset the FOCUS control slightly when the 
INTENSITY control setting is changed. 



Misadjustment of probe compensation is one of the 
sources of measurement error. The attenuator probes 
are equipped with compensation adjustments. To ensure 
optimum measurement accuracy, always check probe 
compensation before making measurements. Probe low- 
frequency compensation is accomplished as follows: 



AUTO DC BALANCE ADJUSTMENT 



1. Preset instrument controls and obtain a baseline trace 
as described in "Initial Setup." Set 20 MHz BW LIMIT 
On (in). 



The 2445 can automatically perform a dc-balance 
adjustment of Channel 1 and Channel 2. This adjustment 
assures that the trace shifts associated with attenuator 
stepping, changing the variable volts per division setting, 

and switching Channel 2 between noninverted and inverted 



2. Connect the two 10X probes (supplied with the 
instrument) to the CH 1 OR X and the CH 2 input con- 
nectors. Observe that the CHANNEL 1 SCALE FACTOR 
on the readout display changes from 10 mV to 100 mV 
when the 10X probe is attached. 



3. Connect the Channel 1 probe (using the probe hook 
tip) to the oscilloscope CALIBRATOR output. 



4. Set triggering controls for a stable display. The dis- 
play should be five cycles of the CALIBRATOR square- 
wave signal, with an amplitude of four divisions. Center the 
display on the screen. 



5. Check the waveform for overshoot and rolloff (see 
Figure 5-1). If necessary, use a small-bladed screwdriver to 
adjust the probe low-frequency compensation for a square 
front corner on the waveform. 



Operator's Checks and Adjustments-2445 Operators 

MATCHING CHANNEL 2 DELAY 

The apparent signal delay in Channel 2 may be adjusted 
up to ±500 ps to match the apparent delay present in any 
of the other three channels. This adjustment is most com- 
monly used to eliminate delay differences between Chan- 
nel 1 and Channel 2 that may be introduced by the probes 
and has no effect on common-mode rejection when ADD 
VERTICAL MODE is selected. Matching Channel 1 and 
Channel 2 delay is accomplished as follows: 



1. Preset the instrument controls and obtain a baseline 
trace as described in "Initial Setup." 



6. Release the CH 1 VERTICAL MODE switch, select 
CH 2 VERTICAL MODE, and connect the Channel 2 probe 
input to the CALIBRATOR output. Observe that the 
CH 2 SCALE FACTOR on the readout display indicates 
100 mV with the 10X probe attached. 



7. Use the Channel 2 POSITION control to vertically 
center the display and repeat step 5 for the Channel 2 
probe. 



NOTE 

Refer to the instruction manual supplied with the 
probe for more complete information about low- 
frequency and high-frequency compensation of 
the probes. 



2. Connect the two 10X probes (supplied with the 
instrument) to the CH 1 OR X and CH 2 input connectors. 



3. Check and adjust, if necessary, the probes' low- 
frequency compensation. Refer to "Probe Low-Frequency 
Compensation" in this section. 



4. Connect both probes via hook tips to a pulse gener- 
ator fast-rise output. 



5. Press in both the CH 1 and CH 2 VERTICAL MODE 
switches. 



6. Set oscilloscope triggering controls for a stable 
display. 





































































































- 












A 


VER COMPEN 


SATED 


Y. 














CORRECT 


N. 




*•*"** 


- 










\U 


MDER COMPENSATE! 


V 










































100 mV 

I 




100 r 


nV \ 




1 ms 

I 










3S3C 


-12 



Figure 5-1. Probe low-frequency compensation. 



7. Set the A AND B SEC/DIV switches to 10 ns. 



8. Adjust the Channel 1 and Channel 2 POSITION 
controls to vertically overlay the two displayed signals. 



9. Pull out the B SEC/DIV switch and observe the 
message CH 2 DELAY - TURN A in the upper right-hand 
corner of the screen. 



NOTE 

The 2445 can be set to preclude operator adjustment 
of Channel 2 delay. If the delay-offset feature is 
disabled, the message CH 2 DLY DISABLED appears 
in the top row of the readout when attempting to 
activate the feature. Refer the instrument to a 
qualified service technician if adjustment of the 
delay matching is required. 



5-3 



Operator's Checks and Adjustments— 2445 Operators 



10. Set X10 MAG ON (button in) and adjust the A 
control until the two signals are overlaid horizontally. 



NOTE 

The A REF OR DLY POS control may also be used 
to make the Channel 2 delay-offset adjustment when 
the feature is enabled. 



11. Push in the B SEC/DIV switch. 



TIMING CHECK 

The CALIBRATOR signal on the 2445 automatically 
changes repetition rate with the setting of the A SEC/DIV 
switch within the range of 100 ms to 100 ns. This feature 
allows the operator to make a quick and easy check of the 
basic operation and adjustment of the oscilloscope timing. 
Use the following procedure: 

1. Preset instrument controls and obtain a baseline trace 
as described in "Initial Setup." 



AMPLITUDE CHECK 



2. Connect a 10X probe to the CH 1 OR X input con- 
nector and connect the probe tip to the CALIBRATOR 
output. 



1. Preset instrument controls and obtain a baseline 
trace as described in "Initial Setup." 



3. Adjust the Channel 1 POSITION control to center 
the display on the screen. 



2. Connect a 10X probe to the CH 1 OR X input con- 
nector and connect the probe tip to the CALIBRATOR 
output. 



3. Adjust the Channel 1 POSITION control to center 
the display on the screen. 



4. Adjust triggering controls to obtain a stable display. 



5. CHECK-Amplitude of the CALIBRATOR signal is 
between 3.88 and 4.12 divisions as measured on the center 
vertical graticule line. 



6. Repeat this procedure using the Channel 2 connector 
and controls. 



4. Adjust triggering controls to obtain a stable display. 



5. CHECK— Timing accuracy by confirming that five 
complete cycles of the square-wave signal are displayed 
over 10 major divisions (±0.1 division) along the center 
horizontal graticule line for all A SEC/DIV settings from 
100 ms to 100 ns. Confirm that the number of cycles 
displayed in 10 divisions goes to 2 1/2 and 1 for respective 
A SEC/DIV settings of 50 ns and 20 ns and that the 
displayed transition time of the signal remains approxi- 
mately the same when the A SEC/DIV switch is changed 
to 10 ns. (The horizontal divisions in which the transition 
time of the signal at 10 ns per division is displayed should 
be two times the horizontal divisions occupied by the 
transition at 20 ns per division.) Return the A SEC/DIV 
switch to 1 ms and confirm that the display changes to 
1/2 cycle over 10 divisions when the X10 MAG switch is 
pressed in. 



5-4 



Section 6—2445 Operators 



BASIC APPLICATIONS 



The TEKTRONIX 2445 Oscilloscope provides an 
accurate and flexible measurement system. After becoming 
familiar with the controls, indicators, operating consider- 
ations, and capabilities of the instrument, an operator can 
easily develop his own convenient methods for making 
particular measurements. The information in this section is 
designed to enhance operator understanding and to assist in 
developing efficient techniques for making your specific 
measurements. Recommended methods for making the 
basic types of measurements with the 2445 are described 
in the procedures contained in this section. 



that the VOLTS/DIV VAR control is in the calibrated 
detent. 



4. Adjust the A TRIGGER LEVEL control to obtain a 
stable display. 



5. Set the A SEC/DIV switch to a position that displays 
a few cycles of the waveform. 



When a procedure first calls for presetting instrument 
controls and obtaining a baseline trace, refer to "Initial 
Setup" in Section 5, "Operator's Checks and Adjustments." 



6. Activate the Delta Volts measurement function by 
momentarily pressing in the AV button. Observe that two 
horizontal cursors and a AV readout appear on the screen. 



INDEX OF PROCEDURES 

Voltage Measurement 6-1 

Voltage Ratio 6-2 

Algebraic Addition and Eliminating 

Common-mode Signals 6-3 

Time Interval 6-4 

Frequency 6-4 

Time Difference Between Two Time-related Pulses . . . 6-5 

Time Ratio 6-5 

Phase Difference Between Two Time-related Signals. . . 6-6 

Small-angle Phase Difference 6-6 

Delayed-sweep Operation 6-7 



The Reference cursor can be positioned by the A REF 
OR DLY POS control, and the Delta cursor can be posi- 
tioned by the A control. Voltage difference between the 
two cursors is displayed by the readout located in the 
upper right-hand corner of the screen. Changing the 
VOLTS/DIV switch position automatically changes the 
readout scale. This scale also automatically compensates for 
the attenuation factor of attenuator probes equipped with 
readout encoding. 



7. Position the two cursors on the desired points of 
the waveform (see Figure 6-1). 



VOLTAGE MEASUREMENT 

The 2445 has a built-in Delta Volts function that 
reduces voltage measurement to a simple process. The 
following procedure may be used to make voltage measure- 
ments between any two points on a waveform (e.g., ac 
peak-to-peak voltages, instantaneous voltage levels, and 
pulse heights). 

1. Preset instrument controls and obtain a baseline trace. 



2. Apply the signal to either the CH 1 OR X or the CH 2 
input connector and select the VERTICAL MODE switch 
to display the channel used. 



3. Set the appropriate VOLTS/DIV switch to display 
between three and eight divisions of the waveform, ensuring 





DELTA 


CURSOR INSTANTANEOUS 
VOLTAGE LEVEL 


s 

c 


A 


1 


O.C 


)V 






AV1 

i 


8.05V ^ 

t t 


VOLTAGE LEVEL 
OF INTEREST 

\ 




















I 


T~ 










; 




















; 




















1 


















I ! 




















■/■ 




t 
i 




■\ 


2 


V 






\ 




1 
20 ms 








REFERENCE CURSOR GROUN 


\ 

D REFERENCE 

3832-13 



Figure 6-1. Instantaneous cic levels. 



6-1 



Basic Applications— 2445 Operators 



To measure peak-to-peak voltage, align the Reference 
cursor with the bottom of the waveform and align the Delta 
cursor with the top of the waveform. 



To measure instantaneous voltage levels, align the 
Reference cursor with ground reference, obtained by 
momentarily switching the Input Coupling switch to GND. 



NOTE 

The VOLTS/DIV switch and the VOLTS/DIV VAR 
control must remain at these settings for the 
remainder of the measurement. 



6. Remove the reference-signal connection and apply 
the test signal to the same input connector. 



8. Read the voltage difference between the two cursors 
from the crt readout. A negative number indicates the 
Delta cursor is below the Reference cursor. 



7. Activate the Delta Volts measurement function 
by momentarily pressing in the AV button. Observe that 
two horizontal cursors and a RATIO readout appear on the 
screen. 



NOTE 

In certain situations, such as comparing a test-signal 
amplitude to a reference amplitude, it may be more 
convenient to position the cursors in the Tracking 
mode. To activate Tracking mode, push in the 
TRACKING button. In this mode, the A REF OR 
DLY POS control will move both cursors equally 
at the same time. The A control will continue to 
move the Delta cursor independently. 



VOLTAGE RATIO 



The Reference cursor is positioned by the A REF OR 
DLY POS control, while the Delta cursor is positioned 
by the A control. The readout in the upper right-hand 
corner of the screen will display the ratio, in terms of 
percent, between the separation of the two cursors and the 
five-division reference signal. When the two cursors are 
separated by five divisions, the readout indicates 100%. 



8. Align the Reference cursor with the bottom of the 
test-signal waveform and the Delta cursor with the top of 
the waveform (see Figure 6-2). 



The Delta Volts function also may be used to measure 
and compute the ratio, in terms of percent, between two 
different signal voltages (e.g., a test voltage and a reference 
voltage). These test and reference voltages may be either 
part of the same waveform or parts of totally separate 
signals. To measure a voltage ratio in the general-case 
situation of two separate signals, use the following 
procedure: 

1. Preset instrument controls and obtain a baseline 
trace. 



2. Apply the reference signal to either the CH 1 OR X 
or the CH 2 input connector and select the VERTICAL 
MODE switch to display the channel used. 



3. Set the appropriate VOLTS/DIV switch to display 



more than five divisions of the waveform. 



VOLTAGE 
RATIO 



I 



RATIO 31 .7% 




REFERENCE SIGNAL 
(FIVE DIVISIONS) 



DELTA 
CURSOR 



TEST SIGNAL 



REFERENCE 
CURSOR 



4. Adjust the A TRIGGER LEVEL control to obtain 
a stable display. 



Figure 6-2. Voltage ratios. 



5. Adjust the appropriate VOLTS/DIV VAR control 
so that the reference portion of the waveform is exactly 
five divisions. 



9. Read the ratio between the test signal and the refer- 
ence signal on the crt readout. If the Reference cursor is 
above the Delta cursor, the readout will show a negative 
number, and this has no other significance. 



62 



Basic Applications-2445 Operators 



NOTE 

In certain situations, such as checking test limits, 
it may be more convenient to use the cursors in the 
Tracking mode. To activate Tracking mode, push in 
the TRACKING button at the same time that AV 
is selected (step 7). In this mode, the A REF OR 
DLY POS control will move both cursors equally 
at the same time. The A control will continue to 
move the Delta cursor independently and can be used 
to preset a desired voltage-ratio test limit. The A REF 
OR DLY POS control can then be used to position 
the test limits (cursors) either on various test signals 
or on various portions of a test signal. 



ALGEBRAIC ADDITION 

AND ELIMINATING 

COMMON-MODE SIGNALS 

With the ADD VERTICAL MODE button pressed in, 
the waveform displayed is the algebraic sum of the signals 
applied to the CH 1 OR X and the CH 2 input connectors 
(CH 1 + CH 2). If the INVERT push button is pressed in, 
the waveform displayed is the difference between the 
signals applied to the Channel 1 and Channel 2 inputs 
(CH 1 - CH 2). When both VOLTS/DIV switches are set 
to the same deflection factor, the ADD trace deflection 
factor is equal to the deflection factor indicated by either 
VOLTS/DIV switch. 



The following procedure shows how to eliminate 
unwanted ac input-power frequency components. Similar 
methods could be used either to eliminate other unwanted 
frequency components or to provide a dc offset. 

1. Preset instrument controls and obtain a baseline 
trace. 



2. Apply the signal containing the unwanted line- 
frequency components to the CH 1 OR X input connector. 



3. Apply a line-frequency signal to the CH 2 input 
connector. To maximize cancellation, the signal applied 
to Channel 2 must be in phase with the unwanted line- 
frequency component on the Channel 1 input. 



4. Select both CH 1 and CH 2 VERTICAL MODE. 



5. Set both VOLTS/DIV switches to produce displays 
of approximately four or five divisions in amplitude. 



6. Adjust the Channel 2 VOLTS/DIV switch and VAR 
control so that the Channel 2 display is approximately the 
same amplitude as the undesired portion of the Channel 1 
display (see Figure 6-3A). 



Two common uses for ADD mode are: (1) the providing 
of a dc offset for an ac signal riding on top of a high dc 
level and (2) the canceling out of undesirable signal com- 
ponents through common-mode rejection. 

NOTE 

The following general precautions should be observed 
when using ADD mode. 

1. Do not exceed the input-voltage rating of the 
oscilloscope or probe. 

2. Do not apply signals that exceed the equivalent of 
about eight times the VOLTS/DIV switch settings, 
since large voltages may distort the display. For 
example, with a VOLTS/DIV switch setting of 0.5, 
the voltage applied to that channel should not exceed 
4 V. 

3. Use Channel 1 and Channel 2 POSITION control 
settings which most nearly position the signal on each 
channel to midscreen, when viewed separately. This 
ensures the greatest dynamic range for ADD mode 
operation. 

4. To attain similar responses from both channels, set 
both the Channel 1 and the Channel 2 Input Coupling 
switches to the same position. 



CH 1 SIGNAL 
WITH UNWANTED 
LINE FREQUENCY 

COMPONENT 



CH 2 SIGNAL 

FROM LINE 

FREQUENCY 

SOURCE 



SIGNAL WITH 

LINE FREQUENCY 

COMPONENT 

CANCELED 

OUT 



V 












*» *" 


^^ 


»*, 






s. 






. X 


> 






X 


\ 


X 










; • 


^ — 


** ** 


v 




- 


X 


i>* 




*'< 










- 

































































































(A) 


CH 


1 AND CH 2 


SIGNALS 




































































- 




















- 




















- 








i iiij..... 

t 










- 








+ 


















+ 


















; 


















4- 

t 
+ 











(B) RESULTANT SIGNAL 



3832-15 



Figure 6-3. Eliminating common-mode signals. 



6-3 



Basic Applications— 2445 Operators 



7. Select both ADD and INVERT, release the CH 1 
and CH 2 buttons, and slightly readjust the Channel 2 
VAR control for maximum cancellation of the undesired 
signal component (see Figure 6-3B). 



by adjusting the VOLTS/DIV VAR control until the wave- 
form exactly fills the screen between the 0% and 100% 
graticule lines, then utilizing the 10% and 90% horizontal 
graticule lines (see Figure 6-4). 



TIME INTERVAL 



To measure waveform periods, align the cursors 
identical points on two adjacent cycles of the waveform. 



to 



The built-in Delta Time function greatly simplifies 
making various timing measurements. To measure the time 
interval between any two points on a waveform (e.g., rise 
time, fall times, and periods), use the following procedure. 

1. Preset instrument controls and obtain a baseline 
trace. 



2. Apply the signal to any vertical input connector and 
select the VERTICAL MODE switch to display the channel 
used. 



3. Set the appropriate VOLTS/DIV switch for a con- 
venient amplitude display of the waveform. 



4. Adjust the A TRIGGER LEVEL control to obtain a 
stable display. 







RISE TIME 
/ 




A1 


0.0 V 




:At 


81.05/zs 


POINT 










































- 














*■>£ 


0% 










































10% POINT - 






























































2V 


/ 






20 MS "^ 


s 






/ \ 

REFERENCE DELTA 
CURSOR CURSOR 

3832-16 



Figure 6-4. Measuring rise times. 



5. Set the A SEC/DIV switch to a position that con- 
veniently displays the complete portion of interest of the 
waveform. 



6. Activate the Delta Time measurement function 
by momentarily pressing in the At button. Observe that 
two vertical cursors and a At readout appear on the screen. 



The Reference cursor is positioned by the A REF OR 
DLY POS control, and the Delta cursor is positioned by the 
A control. A crt readout in the upper right-hand corner of 
the screen displays the time difference between the two 
cursors. Changing the SEC/DIV switch position auto- 
matically changes the readout scale. 



8. Read the time difference between the two cursors 
from the crt readout. If the Delta cursor is left of the 
Reference cursor, the readout will display a negative 

number. 



NOTE 

In certain situations, such as checking test limits, 
it may be more convenient to use the cursors in 
the Tracking mode. To activate Tracking mode, 
push in the TRACKING button. In this mode, the 
A REF OR DL Y POS control will move both cursors 
equally at the same time. The A control will continue 
to move the Delta cursor independently. 



7. Position 
waveform. 



the cursors to the desired points of the 



FREQUENCY 



To measure rise time or fall time, the Reference cursor 
should be aligned to the 10% point on the waveform and 
the Delta cursor should be aligned to the 90% point on the 
waveform. The 10% and 90% points are most easily found 



For frequency measurements, use the same method as 
previously described for waveform periods under "Time 
Interval" measurements, except that in step 6 both the AV 
and At buttons must be pushed in together. The crt readout 
will then display the frequency (1/At) in terms of Hz. 



6-4 



TIME DIFFERENCE BETWEEN 
TWO TIME-RELATED PULSES 



The time difference between two time-related pulses 
can be measured in a manner similar to that previously 
described for measuring time interval. 



1. Using either probes or cables with equal time delays, 
connect one signal to the CH 1 OR X input connector and 
the other signal to the CH 2 input connector. The pro- 
cedure for matching probe delays is found under "Matching 
Channel 2 Delay" in Section 5, "Operator's Checks and 
Adjustments." 



Basic Applications— 2445 Operators 

TIME RATIO 



The Delta Time function also can be used to measure 
and compute the ratio, in terms of percent, between two 
different time intervals (e.g., a test interval and a reference 
interval used to measure a duty cycle). To measure a time 
ratio, use the following procedure: 



1. Preset instrument controls and obtain a baseline trace. 



2. Apply the reference signal to either the CH 1 OR X 
or the CH 2 input connector and select the VERTICAL 
MODE switch to display the channel used. 



2. Select both CH 1 and CH 2 VERTICAL MODE 
switches. 



3. Set TRIGGER controls so that either one (but not 
both) of the signals or a third time-related signal is the 
triggering signal source. 



3. Set the appropriate VOLTS/DIV switch for a con- 
venient amplitude display of the waveform. 



4. Adjust the A TRIGGER LEVEL control to obtain a 
stable display. 



4. Activate the Delta Time measurement function 
and set the cursors to similar reference points (such as 
leading edges) on the two signal displays (see Figure 6-5). 



5. Set the A SEC/DIV switch and the A SEC/DIV VAR 
control to obtain a reference interval of exactly five hori- 
zontal divisions. 



5. Read time difference from the crt readout. 



NOTE 

The A SEC/DIV switch and the A SEC/DIV VAR 
control must remain at these settings for the 
remainder of the measurement. 





TIME DIFFERENCE 

/ 




A 


1 










At 


91 


.8< 


)//S 








' 




















' 




, 


















- 






















REFERE 


NCE 




















COP 


/IPARISON 
SIGNAL 


SIGN/ 

\ 


1- 




















* 




i\ 




























. 














> 


























2V / 1 


V 






\ 


2C 


MS 




REF 


/ \ 

ERENCE CURSOR DELTA CU 


RSOR 

3832-17 



Figure 6-5. Time difference between two time-related pulses 
(cursor method). 



6. If the test interval is part of a different signal, apply 
the test signal to one of the unused vertical-input con- 
nectors and select the VERTICAL MODE switch to display 
the channel used. 



7. Activate the Delta Time measurement function 
by momentarily pressing in the At button. Observe that 
two vertical cursors and a RATIO readout appear on the 
screen. 



The Reference cursor is positioned by the A REF OR 
DLY POS control, and the Delta cursor is positioned by the 
A control. The crt readout located in the upper right-hand 
corner of the screen will display the ratio, in terms of 
percent, between the separation of the two cursors and the 
five-division reference interval. When the two cursors are 
separated by five divisions, the readout indicates 100%. 



6-5 



Basic Applications— 2445 Operators 



8. Align the Reference cursor to the left edge of the 
test interval and the Delta cursor to the right edge of the 
test interval (see Figure 6-6). 



9. Read the ratio between the test 
reference interval from the crt readout. 



interval and the 



If the Delta cursor is left of the Reference cursor, the 
readout will show a negative number. 



NOTE 

In certain situations, such as checking test limits, 
it may be more convenient to use the cursors in 
the Tracking mode. To activate Tracking mode, 
push in the TRACKING button. In this mode, the 
A REF OR DL Y POS control will move both cursors 
equally at the same time. The A control will continue 
to move the Delta cursor independently. 



2. Using either probes or cables with equal time delays, 
apply the reference signal to the CH 1 OR X input con- 
nector and the comparison signal to the CH 2 input 
connector. The procedure for matching delays is found 
under "Matching Channel 2 Delay" in Section 5. 



3. Press in both CH 1 and CH 2 VERTICAL MODE 
buttons. 



4. Set the Channel 1 and Channel 2 VOLTS/DIV 
switches and adjust the VAR controls to obtain equal 
amplitudes of the reference and the comparison signals. 



5. Use the Vertical POSITION controls to center both 
displays vertically within the graticule area. 



6. Set the A SEC/DIV switch and the SEC/DIV VAR 
control to display one cycle of the reference signal over five 
horizontal divisions. 



TIME RATIO 
(DUTY CYCLE) 



T" 

A1 



0.0 V 



REFERENCE 
CURSOR 



2 V 



RATIO 32.9% 



^C 



-DELTA 
•t CURSOR 



20.1 ms 



TEST 
"SIGNAL 



REFERENCE 
- INTERVAL — +- 
(5 DIVISIONS) 



3B32-18 



Figure 6-6. Time ratios (duty cycles). 



PHASE DIFFERENCE BETWEEN 
TWO TIME-RELATED SIGNALS 

The phase difference between two signals of equal 
frequency is determined in a manner similar to that 
described in the preceding procedure for measuring time 
ratio. To measure the phase difference between two time- 
related signals, use the following procedure: 

1 . Preset instrument controls and obtain a baseline trace. 



7. Activate the 1/Delta Time measurement function by 
pressing in both the At and the AV buttons together. 



8. Use the A REF OR DLY POS control to align the 
Reference cursor with a zero-crossing of the reference signal 
(see Figure 6-7). Use the center horizontal graticule line as 
the zero reference for aligning the crossover point. 



9. Use the A control to align the Delta cursor with 
the nearest zero-crossing of the comparison signal on the 
same slope as the reference signal zero-crossing. 



10. Read phase difference in degrees from the crt readout. 



SMALL-ANGLE PHASE DIFFERENCE 



If the phase difference between the two signals being 
measured is small, increased resolution for setting the 
cursors can be obtained by using the X10 MAG feature. 



1. Perform steps 1 through 6 of the preceding "Phase 
Difference" procedure to obtain a five-division display of 
one cycle of the reference and comparison signals. 



2. Use the Horizontal POSITION control to move the 
zero-crossing points of the signals being measured to the 
center vertical graticule line. 



6-6 



REFERENCE. 
CURSOR \ 



ZERO 

CROSSING 

REFERENCE 

SIGNAL 




ZERO CROSSING 

COMPARISON 

SIGNAL 



3832-19 



Figure 6-7. Phase difference between two time-related signals. 



3. Press in the X10 MAG push button to obtain the 
magnified display and use the Horizontal POSITION and 
A REF OR DLY POS controls to align the reference 
zero-crossing with the Reference cursor. 



4. Align the Delta cursor with the second comparison 
zero-crossing (see Figure 6-8). 



Basic Applications— 2445 Operators 

DELAYED-SWEEP OPERATION 

The 2445 offers three delayed-sweep operating modes: 
the A Intensified Sweep, the A Intensified Sweep alternated 
with the B Delayed Sweep, and the B Delayed Sweep. 
Appropriate use for these modes varies with the particular 
application, but in general they are used most frequently 
for making timing measurements and for examining specific 
points of interest within a waveform or pulse train. 



A Intensified Horizontal Display Mode 

The A Intensified Horizontal Display mode is entered 
by pulling out the B SEC/DIV knob (PULL-INTEN) while 
both the A SEC/DIV and the B SEC/DIV switches are at 
the same setting. In this mode only the A Sweep is 
displayed, with a short intensified zone imposed on it. The 
position and length of the intensified zone indicates the 
delay-time position and the B Sweep interval respectively. 
A DLY readout appearing in the crt display gives the time 
delay between the start of the A Sweep and the start of the 
B Sweep. Positioning the intensified zone to a point of 
interest on the A Sweep trace is accomplished using the A 
REF OR DLY POS control. Rotating the control continu- 
ously changes the DLY readout seen on the crt. With the B 
TRIGGER MODE set to RUN AFT DLY, the position of 
the intensified zone on the A Sweep trace also is continu- 
ously variable and follows the delay change smoothly. 



5. Read the (magnified) phase difference in degrees 
from the crt readout. Divide this reading by 10 to obtain 
the correct phase difference between the two signals. 



DIVIDE BY 10 



REFERENCE. 
CURSOR 



ZERO CROSSING 

REFERENCE 

SIGNAL 




> 100 mV> 200 m 

i i i i 



i CROSSING 
^COMPARISON 
SIGNAL 



10.4 ns 



DELTA CURSOR 



3832-20 



Figure 6-8. Small-angle phase difference. 



NOTE 

If the B TRIGGER MODE is set to TRIG AFT DL Y 
for triggered B Sweep operation, the A REF OR DL Y 
POS control does not continuously position the 
intensified zone on the A Sweep trace. In this case, 
the intensified zone jumps to each succeeding B 
Trigger point within the A Sweep interval as delay 
time is changed. 



Once the intensified zone is positioned at the point of 
interest, switching to the Alternate Horizontal Display 
mode (TURN-ALT) offers a convenient sweep display for 
either examining that point in greater detail or making 
time measurements. 



Alternate Horizontal Display Mode 

In this mode, both the A Intensified Sweep and the B 
Delayed Sweep traces are displayed. The mode is entered 
by first entering the A Intensified Horizontal Display mode 
(PULL-INTEN) then setting the B SEC/DIV switch to a 
faster sweep speed than the A SEC/DIV switch setting. The 
length of the intensified-zone display now becomes a 
function of the B Sweep speed. Increasing the B Sweep 



6-7 



Basic Applications— 2445 Operators 



speed shortens the length of the zone. The intensified zone 
on the A Sweep trace is used to identify the point of 
interest to be examined or measured, while the alternate B 
Delayed Sweep trace magnifies and displays the intensified 
segment. Apparent horizontal magnification of the wave- 
form occurs as a result of displaying the selected portion of 
the A Sweep at a faster B Sweep speed. 



Vertical separation of the A and B Sweep traces is 
variable using the TRACE SEP control. The control has 
enough range to position the B Sweep trace from zero 
(overlayed on the A Sweep trace) to three or more divisions 
downward from the A Sweep trace. 



Time measurements can be readily made on waveforms 
by employing the DLY readout and the A REF OR DLY 
POS control. Delay time from the A trigger point to the 
beginning of the B Sweep is read directly from the DLY 
readout in the crt display. After noting a first delay-time 
position, a second measurement point can be aligned with 
the same reference graticule line, and the new delay time 
read. Time difference between the two points is then 
determined by computing the difference between the two 
delay-time readings. The computed time difference between 
the two delay times is more accurate than either of the 
delay-time readings. 



B Delayed Horizontal Display Mode 

Once the point of interest to be examined or measured is 
identified, the A Intensified Sweep trace can be eliminated 
to provide an uncluttered display for ease of viewing. 
Displaying only the B Delayed Sweep (PUSH-B) is accom- 
plished by pushing in the B SEC/DIV knob after first 
establishing the Alternate Horizontal Display mode. Pulling 
the B SEC/DIV knob back out returns the A Intensified 
trace to the display, if needed to reidentify a measurement 
point. Rotating the B SEC/DIV knob back to the same 
setting as the A SEC/DIV switch, with the B SEC/DIV 
knob pushed in, locks the two knobs together and returns 
the Horizontal Display mode back to A Sweep only. 



Delta Time Feature with Delayed Sweep 

The Delta Time function can be used in any of the 
delayed-sweep modes to obtain direct-reading time- 
difference measurements. When activated, two separate 
B Delayed Sweep intervals are produced in the A Sweep 
interval. Delay time for each B Sweep interval is 
independently adjustable. The A REF OR DLY POS 
control positions one of the delay times, usually referred 
to as the Reference intensified zone or the Reference delay. 
Positioning of the second delay time, referred to as the 
Delta intensified zone or the Delta delay, is accomplished 
with the A control. 



NOTE 

If the Tracking mode of delay-time positioning is 
selected (T RACKING /INDEP button in), the A REF 
OR DL Y POS control simultaneously moves both the 
Reference and the Delta delays equal amounts. The 
A control, however, continues to independently 
position the Delta delay regardless of the position of 
the TRACKING/INDEP button. 



Delta Time measurements using the A Intensified 
Horizontal Display mode are made by simply setting the 
start of each intensified zone to the separate measurement 
points and noting the At readout in the crt display. This 
method produces the least accurate results, since it is 
difficult to determine exact alignment with the measure- 
ment points. 



Much more accurate measurements are possible using 
the Alternate Horizontal Display mode. In this mode, a 
separate B Delayed Sweep trace is present for each 
displayed intensified zone. As explained before, the inten- 
sified zones are positioned to the points of interest; but 
instead of aligning the start of the zones to the measure- 
ment points, both the Reference and the Delta delays are 
adjusted to overlay the two points precisely, using the 
respective B Delayed traces. An example application of this 
method is given in the following procedure. 



This procedure describes the steps necessary to make 
time measurements between two time-related pulses applied 
on separate input channels. However, the same principles 
apply for measuring time differences between successive 
pulses, pulse periods, or other time intervals on a single- 
channel input signal. 



1. Preset instrument controls and obtain a baseline trace. 



2. Using either probes or cables with equal time delays, 
apply a known reference signal to the CH 1 OR X input 
connector and apply the comparison signal to the CH 2 
input connector. 



NOTE 

If the repetition rates of the pulses to be measured 
are not the same, use the slower repetition-rate signal 
as the Trigger SOURCE signal. Using the faster 
repetition-rate signal as the Trigger SOURCE will 
present multiple triggering-point possibilities during 
the period of the slower signal. 



3. Select both CH 1 and CH 2 VERTICAL MODE. 



6-8 



Basic Applications-2445 Operators 



4. Set both VOLTS/DIV switches to produce displays 
of approximately four to five divisions in amplitude. 



5. Press up on the Trigger MODE switch to acquire 
the correct AUTO LVL for triggering. 



11. Rotate the B SEC/DIV switch three to six positions 
clockwise to obtain a high degree of resolution of the 
measurement points. Use X10 MAG as required for 
optimum resolution. Observe that two alternate B Delayed 
Sweep traces {one for each intensified zone) appear in the 
display. 



6. Use the Channel 1 and Channel 2 POSITION controls 
to vertically center both displays. 



7. Set the A SEC/DIV switch to display the measure- 
ment points of interest within the graticule area. 



12. If desired, the B Delayed Sweep traces can be 
displayed alone, without the A Intensified trace. Pressing 
in the B SEC/DIV knob eliminates the A Intensified trace 
from the display. 



8. Activate the A Intensified Sweep by pulling out the 
B SEC/DIV knob. 



9. Activate the Delta Time measurement function by 
momentarily pressing the At switch; select the independent 
mode of delay-time positioning (TRACKING/INDEP 
button out). 



10. Adjust the A REF OR DLY POS control to align 
the start of the Reference intensified zone with the start of 
the reference-signal point of interest. Use the A control 
to align the start of the Delta intensified zone with the start 
of the comparison-signal point of interest (see Figure 6-9A). 



13. Center the B Delayed traces vertically using the 
Channel VERTICAL POSITION controls and the TRACE 
SEP control as necessary. 



14. Adjust both the A REF OR DLY POS control and 
the A control to superimpose the measurement points of 
the two B Delayed Sweeps (see Figure 6-9B). 



15. Read time difference directly from the crt At 
readout. 



CHANNEL 1 (REFERENCE) 
REFERENCE INTENSIFIED ZONE 



50% / 
AMPLITUDE " 
LEVEL I" 



A1 -0.28 V 




1 V 



1 V 




| 20 ms 



CHANNEL 2 
(COMPARISON) 



DELTA 

INTENSIFIED 

ZONE 



(A) A TRACE 



INTERVAL 

BEING 
MEASURED 



A1 - 0.28 V 



~| j Atj 91.80/js' 



TIME 
DIFFERENCE 



CH 2 SIGNAL 



- CH 1 SIGNAL 



1 V 



1 V 



->L 



J 



CH 1 SIGNAL 



CH 1 AND CH 2 

SUPERIMPOSED 



2 lis 



(B) B TRACE 



3832-21 



Figure 6-9. Time difference between two time-related pulses (delayed-sweep method). 



6-9 



Section 7—2445 Operators 



OPTIONS AND ACCESSORIES 



INTRODUCTION 



POWER CORD OPTIONS 



This section contains a general description of instrument 
options available at the time of publication of this manual. 
Also included is a complete list (with Tektronix part num- 
bers) of standard accessories included with each instrument 
and a partial list of optional accessories. Additional 
information about instrument options, option availability, 
and other accessories can be obtained either by consulting 
the current Tektronix Product Catalog or by contacting 
your local Tektronix Field Office or representative. 



OPTION 1R 



When the 2445 Oscilloscope is ordered with Option 1R, 
it is shipped in a configuration that permits easy installation 
into a 19-inch-wide electronic-equipment rack. 



An optional rear-support kit also is available for use 
when rackmounting the 2445. Using this optional rear- 
support kit enables the rackmounted instrument to meet 
all electrical and environmental specifications of the 
standard 2445 Oscilloscope. 



Connector-mounting holes are provided in the front 
panel of the rackmounted instrument. These enable con- 
venient accessing of the four BNC connectors (CH 2 
SIGNAL OUT, A GATE OUT, B GATE OUT, and EXT Z 
AXIS IN) located on the rear panel. Additional cabling 
and connectors required to implement any front-panel 
access to the rear-panel connectors are supplied by the 
user; however, these items can be separately ordered 
from Tektronix. 



Instruments are shipped with the detachable power-cord 
configuration ordered by the customer. Descriptive infor- 
mation about the international power-cord options is 
provided in Section 2, "Preparation for Use." The following 
list identifies the Tektronix part numbers for the available 
power cords and associated fuses. 



Option A1 (Universal Euro) 

Power cord (2.5 m) 161-0104-06 

Fuse (1.6 A, 250 V, 

5x20 mm. Quick-acting) 159-0098-00 



Option A2 (UK) 

Power cord (2.5 m) 161-0104-07 

Fuse (1.6 A, 250 V, 

5x20 mm. Quick-acting) 159-0098-00 



Option A3 (Australian) 

Power cord (2.5 m) 161-0104-05 

Fuse (1.6 A, 250 V, 

5x20 mm. Quick-acting) 159-0098-00 



Option A4 (North American) 

Power cord (2.5 m) 161-0104-08 

Fuse (2 A, 250 V, AGC/3AG, 

Fast-blow) 159-0021-00 



Complete rackmounting instructions are provided in a 
separate document shipped with the 2445 Option 1R. 
These instructions also contain appropriate procedures to 
convert a standard instrument into the Option 1R con- 
figuration by using the rackmounting conversion kit. 



Option A5 (Switzerland) 

Power cord (2.5 m) 

Fuse (1.6 A, 250 V, 

5 x 20 mm, Quick-acting) 



161-0154-00 
159-0098-00 



7-1 



Options and Accessories— 2445 Operators 



STANDARD ACCESSORIES 



OPTIONAL ACCESSORIES 



The following standard accessories are provided with 
each instrument: 



The following optional accessories are recommended 
for use with the 2445 Oscilloscope. 



Qty Description 


Part Number 


Description 


Part Number 


2 Probes (1 OX, 1.3 m) with 
Accessories 


010-6131-01 


Protective Cover, Waterproof, 
Blue Vinyl 


016-0720-00 


1 Accessory Pouch, 
Snap Fastener 


016-0692-00 


Probe Package {use with 
standard-accessory probes for 
added input-signal connections) 


010-6131-01 


1 Accessory Pouch, 
Zip-lock Fastener 

1 Operators Manual 


016-0537-00 
070-3830-00 


Rackmounting Conversion Kit 

Rear-Support Kit (for use with 
rackmounted instruments) 


016-0691-00 
016-Q096-00 


1 Service Manual 
1 Reference Card 
1 Fuse (2 A, 250 V, AGC/3AG) 


070-3829-00 
070-4178-00 
159-0021-00 


Polarized Collapsible Viewing 
Hood 

Folding Viewing Hood, 
Light-shielding 


016-0180-00 
016-0592-00 


1 Power Cord (installed) 

1 CRT Filter, Blue Plastic 
(installed) 


161-0104-00 
378-0199-00 


Collapsible Viewing Hood, 
Binocular 

Oscilloscope Camera 


016-0566-00 
See C30B Series 


1 CRT Filter, Clear Plastic 


378-0208-00 


SCOPE-MOBILE Cart 


200C 


1 Front-Panel Cover 


200-2742-00 


Carrying Strap 


346-0058-00 



7-2 



Appendix A-2445 Operators 



POWER-UP TESTS 



Power-up tests are divided into two main parts: Kernel 
tests and Confidence tests. 



KERNEL TESTS 



Brief descriptions of the tests are listed in Table A-1. A 
Confidence test failure may not render the instrument 
inoperable. The instrument may still be placed into the 
operating mode by pressing in the A/B TRIG button; 
however, it may not meet all specifications. 



The Kernel tests confirm proper operation of the mem- 
ory associated with the basic instrument's microprocessor 
(RAM and ROM) and of any instrument options that are 
present. A failure of a Kernel test is indicated by a flashing 
TRIG'D indicator on the instrument front panel. 



Even with a Kernel failure, the instrument may still be 
put into the operating mode by pressing in the A/B TRIG 
button. However, its operation will be unpredictable. 



CONFIDENCE TESTS 

The Confidence tests are performed after successful 
completion of all Kernel tests. Confidence testing for any 
options present in the instrument will automatically be 
included. A failure of any Confidence test at power on is 
indicated in the bottom line of the crt readout. The failure 
display has the following format: 

TEST XX FAIL YY 

where XX is the two-digit hexadecimal test number and YY 
represents the failure code for the failed test. 



Table A-1 
Confidence Test Numbers and Descriptions 



Test Number 



02 



03 



04 



05 



Description 



IRQ— Checks that interrupts are occurring 
and that correct time interval exists 
between interrupt occurrences. 



SWITCH STUCK-Checks for momentary 
switches that may be stuck closed. 



READOUT BOARD-Checks interfaces 
with the Readout circuit board and the 
readout RAM. 



EAROM-Checks the EAROM interface 
and verifies the calibration constants stored 
in the EAROM. 



MAIN BOARD-Partially checks the Main 
circuit board by operating the Auto Level 
function on the Line Trigger source. 



A-1